No. 875.

LONDON, SATURDAY, JUNE 6, 1840. [1839-40.

LECTURES BY M. DE BLAINVILLE ON

COMPARATIVE OSTEOLOGY.

THE

COMPARATIVE OSTEOGRAPHYOF THE

SKELETONAND DENTAR SYSTEM

IN THE FIVE CLASSES OF

VERTEBRAL ANIMALS,RECENT AND FOSSIL.

BY M. H. M. DUCROTAY DE BLAINVILLE,Member of the Institute of France.

WITH GRAPHIC DELINEATIONS BY M. WERNER;

EDITED (FROM THE FRENCH) AND

ADDITIONALLY ILLUSTRATED

WITH NUMEROUS NOTES, OBSERVATIONS,AND DRAWINGS,

BY ROBERT KNOX, M.D.,Edinburgh; Corresponding Member of the

French Academy of Medicine, &c. &c.

OSTEOGRAPHY OF THE PRIMATES.(Continued.)

Sapajous (Cebus)—Cebidœ (Swain)—Ameri-can Monkeys.*

* It is rather a singular circumstance, thatAmerican Monkeys are scarce in Britain, atleast we have found it so in the ModernAthens (Edinburgh), where, with the excep-tion of one or two skeletons in our own pri-vate museum, we were unable to meet withany skeletons of these animals. A livingspecimen of the Atèles had got into the pos-session of the Edinburgh Zoological Gardenlately, and, like by far the greater proportionof these animals, it died (poisoned, we think,in consequence of being fed on any thing butits proper food!); and, although the members

of the Zoological Society lay strong claims toa love of science and scientific investigation,the dead Atèles was permitted to putrify, and,ultimately, completely disappear, withoutany examination whatever being made ofany part of its anatomy. This will, no

doubt, appear strange to our readers, andwe have only to add, that we have offeredour services to the Directors, and stated ouranxious desire to promote the cause of sci-ence, with our time and talents, whenever anopportunity offered, arising from the frequentdeath of specimens in all such collections.—R. Knox.

THE Primates, which form the subject ofthis our second fasciculus, are those whichwere designated for the first time under thedenomination collectively of Sapajous, byBuffon, and for which we have admitted the

Latin name of Cebus (using Sapajou more asa generic term), given to them by Erxleben,although thus borrowing from the ancients,who certainly were unacquainted with a.

single species of the family ; the group, inother respects, resembles the preceding Simian(tSMMC), very readily characterised, how-ever, by the more terminal disposition of thenostrils, and being more widely separated ;by the thumb being never really opposable ;and, lastly, by the number of the molar teeth,which are either five or six on each side ofeach jaw ; there are always three ante1’ÎoJ’

molars, instead of two, an arrangementwhich is constant in the Simise (:?MMt<tc),orApes and Monkeys of the Old World.

This distinctive character of the Cebidwwould alone suffice to show in their organi-zation an evident degradation, although thisdegradation in structure is not, after all, verygreat; but we shall now proceed to provethis by an examination of their osteographyand odontography.

OF THE BONES OF THE SKELETON.

The Cebidae being animals even still morearboreal than the Simias (Simiadae), it iseasy to imagine that they seldom attain morethan a median height, and that their skeleton,as a whole, is generally more suited for

seizing and clinging to objects, such as thebranches of trees.The bones, however, which compose their

skeleton, do not appear to be more solid,more resisting, than those of the Simiadae, orAfrican Monkeys. It appears to me, how-ever, that the epiphyses of the bones unite at

354

an earlier period, and the processes, ridgesfor muscular insertion, the grooves, and, inshort, every thing which indicates long-sus-tained muscular action, is generally moredeveloped.The bones composing the skeleton are,

perhaps, more numerous also, than in theother primates, more especially because thetail is always very long, often prehensile,and seeing that there are more vertebrae in agiven length of tail.With regard to the general, and, at the

same time, minute arrangement of the bones,the skeleton resembles, almost in every re-

spect, that of the Simiadae, if it is not, per.haps, that the power of assuming the erect(vertical) position is still more dimini3hed,as also that of the sitting posture, the quad.ruped form being clearly more marked, aswe shall now proceed to show.For this purpose, and pursuing the plan

which we have already adopted in our oste.ography of the Simiadas, we proceed to

select, for a type of comparison, the skeletonof a species about the middle of the series,viz., the Sapajou or Sajou (Cebus Apella), andwe shall compare with it the species in theascending and descending scale.

Fig. 37.

Sapajou Brun. (Cebus Apella.)Sapajou, Sajou, Cebus Apella, Desm.Simia Apella, Linn.Habitat, French Guayna and Terra Firma, but not from the Brazils.The skeleton viewed in profile. Completely adult, after an artificial skeleton in the

old collection, and in which, from inattention, no doubt, the atlas has been reversed in itsposition, that is, turned upside down, and which circumstance I had not noticed untilthe drawing was finished.

The entire vertebral column, including thehead, is composed of fifty-five vertebras, fourcephalic, seven cervical, fourteen dorsal, fivelumbar, three sacral, and twenty-two coccy-geal, so that it never presents that truncatedappearance which we have remarked insome species of the Simiadae. The neck, atits thoracic extremity, or root, is consider-ably curved upward, so as to elevate itself,and present to the head a point of support,at its free extremity. The spinal columnpresents, for nearly its whole length, a gentlecurve, excepting just at the root of the pelvis,and especially in the tail, which is bothrolled and twisted spirally, and, finally, thecolumn is pointed both anteriorly and pos-teriorly.

The cephalic vertebras of the Sapajou (C.Apella), which we have selected for our type,are arranged in rather a different mannerfrom the Guenons, which we also took as atype of the Simiae or African Monkey; sothat the arch, at the point of union of thefrontal vertebra, with that of the nasal(second with the first), is much more marked,and recals strongly the similarity to the hu-man species; and as the cephalic (maxillary)appendages are, at the same time, very short,falling rapidly from the root of the nose, andseeing that the cranium is more expanded asa whole, and especially the anterior part, thefacial angle becomes, consequently, muchgreater. It is also necessary to observe thatthe condyles of the occipital bone, being a

355little more anterior, the occiput is evidentlymore projecting posteriorly, and which givesto the cerebral case a greater extent, and amore oval shape, being at the same timemore extended at the sides. Each cephalicvertebra, in particular, offers, in other re-spects, but slight differences, in the corre-

sponding vertebrae in the Callitriche (P. Sa-boeus), only the frontal, properly so called,pushes itself, generally, at a very earlyperiod, between the parietal, and the occipi-tal crest even, is less developed ; the sagittalcrest (parietal crests) is seldom, if ever,developed, the temporal fossas are alwaysconsiderably removed from each other, andthe frontal crests scarcely developed, even inthe aged male specimen.The most differential points presented by

the interior or cranial cavity of the Sapajou(C. Apella), appears to be in the swelling outof the orbitar vaults, thus diminishing thefrontal excavation, and narrowing the cribri-form plate of the ethmoid bone ; the approxi-mation of the optic foramina, and thesphenoidal fissures ; the absence of the ante-rior clinoid processes ; lastly, by a vestigeor trace of a cerebellar lamina (osseous ten-torium cerer’fedti), by the prolongation of thesolid angle of the rocky part of the temporalbone externally.The cephalic appendages or jaws present

differences of greater importance, and, con-sequently, the cavities or fossae, which theyform, or contribute to form ; first, becausethey are evidently much shorter, as we havealready stated, the length of the palate notexceeding the half of the whole basilar

length, and, afterwards, by other peculiari-ties sufficiently evident.With regard to the upper jaw, the posterior

palatine root (internal pterygoid) is large andhigh, so as to nearly touch the rocky part ofthe temporal, and form, with the externalpterygoid process (similarly shaped) but stillof larger dimepsions, a large and deep ptery- igoid fossa. The lachrymal root of the upper

Ijaw, always completely orbitar, presents awell marked semi-groove.leading to astraight,compressed canal (nasal), half composed ofthe lachrymal, and half of the maxillary bone.The jugal (malar) root of the upper jaw,narrow in its orbitar margin, or without themarginal ridge, is pierced with a malar

foramen, of moderate dimensions, but muchlarger than in any of the Simiadas ; the max-illary, which leaves in the orbit, between itand the posterior sphenoid, a fissure and alarge foramen posteriorly, is very short, and Ipresents on its margin six alveoli, and ante-riorly, one or two suborbitar foramina; andthe premaxillary (incisive) as in the Calli-triche (P. Sabaeus), surrounds entirely thenasal orifice ; but the ascending (nasal) por-tion is less sloped, and of less dimensions, inits horizontal portion than in the Callitriche.The incisive foramina are oval, and of muchsmaller dimensions.

In respect to the nasal cavities, they areshorter than in the Guenons ; but a littlemore dilated perhaps, particularly at theirorifices. The nasal lateral masses of theethmoid bone are small, and form a smallsuperior turbinated bone, in the form of asimple longitudinal plate, curved slightlybelow; next, a middle turbinated bone, withfour laminae, two directed superiorly, and twoinferiorly, which three grooves separate fromeach other; lastly, the inferior turbinatedbone, rather small, having its fundamental,or articulating plate of bone, bifurcated atits extremity, each division being itselfslightly enlarged at its terminal edge.The inferior cephalic appendage, or lower

jaw, is still more characteristic in the Sapa-jous than the superior. The rocky bone hasstill very nearly the same form and propor-tion ; it is similarly perforated, inferiorly andposteriorly, by the carotid canal; the pro-montory or projection of the cochlea, on itsexternal aspect, is pretty considerable ; andthe two &thorn;nestrae, or exterior openings, verynear each other; the vestibular opening, verymuch cut down, is much smaller than theopening leading to the cochlea, which is verylarge. The ossicula auditfis, generally verysmall, are pressed up into a corner in thesuperior wall of the tympanum ; the stapes,with its usual form, completely concealed inthe fossa of the fenestra ovalis; the orbicular,very distinct and evidently excavated; theiricus, short and thick, even in its branch, whicharticulates with the orbicular; and, lastly, themalleus, whose head is large, without beingset off on a neck, the handle massive and short,and its horizontal or superior processes wellmarked. With respect to the tympanum,it is larger than in the Simiadce, and, parti-cularly, the external auditory canal is ex-tremely short, and remarkable for its greatdiameter; the mastoid portion of the temporalis large, its process not more extended(swollen) than in the Callitriche (P. <S’a&<BMa),but the squamous portion of the temporal isvery little extended, its superior edge almosthorizontal, reaching only the elevation of thelower floor of the orbit; there is a largevenous foramen at the posterior root of thecondyloid process, which is strong; the con-dyloid cavity is transverse, and deep poste-riorly, and the zygomatic process is suffi-

ciently large.With regard to the mandible (dentar por-

tion of the jaw) ,properly speaking, its twobranches, short and large, unite at an angle,nearer a right angle than in the Callitriche(P. Saboeus), and the angular process isevidently more marked, forming a roundedprojection. The symphysis is also a littlemore oblique, and not so long, the two sides

enclosing a parabolical figure, shorter andopener. The anterior opening of the dentarcanal is not so near the base or lower marginof the jaw, but in other respects equally

356

plumb with the interval, between the firstand second anterior molar teeth.The cervical vertebrae form a neck, still

shorter than in the Simiadee, the vertebraethemselves are more locked, that is, theirarticulations are all closer.The Atlas has, properly speaking, no in-

ferior spinous process, but rather a kind oftubercle looking backwards.The Axis has its superior spinous process

dilated a little in the form of the handle of ahammer.’ *

The three intermediate cervical (3, 4, and5) double each other very much, not onlywith regard to the laminae, but the bodies,and the processes are generally small andslender.The transverse processes of the sixth verte-

bra have their internal lobes (anterior tuberclein human anatomy) dilated, and its spinousprocess sometimes nearly as long as the

seventh, or prominent vertebra. The trans-verse processes of the seventh vertebra arelong, delicate, and always imperforate attheir base.The fourteen dorsal vertebra3 are, like the

cervical, more locked than in the Callitriche(P. Sabaeus), the twelve anterior, havingtheir spinous processes directed backwards,particularly towards the last, and the thir-teenth and fourteenth dorsal vertebrae, or lasttwo, have all the characteristics of lumbarvertebrae ; their spinous processes are well-veloped, only, the last of the twelve anterior,or true dorsal, is larger, not unlike the lum-bar vertebrae, although looking backwards,instead of being scalanol’d, as in the Calli-triche (P. Saboeus.)The five lumbar vertebras have their spi-

nous processes proportionally larger, thetransverse narrower, more oblique from be-fore ; those of the last lumbar vertebrae are thelargest, not bifurcated, and the styloid pro-cesses of the posterior articular shorter andmore obtuse. They present, in addition,towards the posterior margin of their arch, anarrow fissure, into which penetrates the an-terior margin of the spinous process of thevertebra which follows.The sacrum, formed of three vertebras, of

which, the articular or anterior has its spinousprocess greatly developed, very similar tothose of the lumbar.The tail, though shorter than in the Calli-

triche (P. Saboeus), is, nevertheless, formedof a greater number of vertebra, at least, in agiven length, there are fewer vertebrae in the I

* In the skeleton of the Cebus Apella, IFig. 37, this process (unhappily placed bythe person who articulated the skeleton onthe lower aspect of the neck instead of theupper) is deeply fissured mesially, throughoutits whole depth, thus rendering it deeplybifurcated at the summit; but we imaginethis to be an anomaly, and by no means apermanent character.

tail of the Guenon, our African type, than inthat of the Sapajou (Cebus Appella), our

American type; there are, also, a greaternumber (five, or rather, four) of completevertebrae ; in other respects, they are verysimilar, and there are the same number ofthe V shaped bones found on the inferioraspect of the tail.

OF THE INFERIOR MEDIAN SERIES OR

STERNEBRIE.

The hyoid in the Sapajou (C. Apella), hasits body larger, more excavated posteriorly,with its margin thin and very much folded an-teriorly ; the styloid horns are delicate, andformed of two portions, the one basilar, ster-nebroid, the other terminal, styloid ; thelaryngeal horns are, on the contrary, verylarge, particularly their base.The sternum, like the series of dorsal ver.

tebrae, with which it is analagous, is a littleshorter, more heaped together, as it were;but it is, in other respects, composed of thesame number of sternebrse as in the Calli-triche,* and evidently of the same form, al-though all the sternebras, and particularlythe last, are evidently larger. Upon thewhole, it is the median sternebra which isthe largest, the two anterior and the twoposterior decreasing as they become elon-gated.We have little to say concerning the ribs;

there are fourteen pairs, of which nine aresternal and five asternal ; they are propor-tionally a little stronger and larger than inthe African typical Monkey.

With regard to the sternal appendages(cQ1,tiltlges of prolongation), they appear to be,on the contrary, rather slender, and propor-tionally larger.

The limbs of the Sapajous (C. Apella) are,generally speaking, shorter than those of theGuenons (P. Saboeus), and een, perhaps, alittle more equal in length.With regard to the anterior, the scapula is

generally smaller, and more oblique, by theanterior and superior angle beingdepressed;the proportion of the fossas is still nearly thesame, and the spine, equally elevated, is ter-minated by an acromion of the same form,that is to say, flat, and slightly recurved infront; the same remarks apply to the cora-coid process, which is bent strongly inwards;and in descending, vertically and a little in-wards ; but the tuberosity, at its root, isstrongly marked, spreading out and risingupwards, which, we observe, tends to convertinto a hole, a deep fissure which exists onthe anterior superior margin, and alwayswell-marked in the Simiadte, or AfricanMonkeys.

* As in the Simlae, we sometimes find inthe sternum of the Sapajous, that the intervalbetween the sixth and seventh sternebraossifies, and in that case there are eightsternebrae in all, when the apparatus is con-sidered in the young specimen.

357The clavicle, which can easily be recog-

nised by its remarkable double curve, almostin the form of the letter S, and its largearticulation, with the manubrium of thesternum, is certainly stronger than in theCallitriche (P. 8(ibo?us), and even longer; itarticulates extensively with the acromion

process of the scapula.The humerus is proportionally shorter,

since it scarcely equals in length the thirteenanterior dorsal vertebrae, whilst in the Calli-triche (P. Sab&oelig;us) it equals the whole ofthe dorsal vertebrae ; it is besides less bent,

. and, as it were, less angular in its lengthor extent of the deltoid insertion ; the inter-nal tuberosity is more sloping than the ex-ternal, which, however, is still the largest;the deltoid impression is a little indistinct;the inferior (distal) extremity is thinner, and,upon the whole, broader than in the Gue-nons (P. Saboeus) ; the external ridge is alsomore developed ; the internal tuberosity isperforated with a pretty large oblique fora-men, which does not exist in any of the

Simiadae, and thus forms an important gene-ric character; lastly, the pulley occupies aslarge a space as the tuberosity in the radio-cubital articulation.The radius nearly equals the humerus in

length, and is very similar to that of theGuenons (P. Saboeus) ; perhaps it is a littlestronger, its head is a little more trans-

verse, its tuberosity is rather stronger, anddescends further down on the shaft of the ibone than in the typical African monkey.The Ulna is, proportionally, still stronger,

more arched in the opposite direction tothat of the radius, and its olecranon processis a little thicker, more angular, and evenmore oblique, than in the Callitriche (P.

iSaboeus). !

Fig. 38.

Hand, with the distal extremities of theradius and ulna, viewed from its dorsal orextensor aspect.

Fig. 39.

Same band, viewed from its internal or radial margin.

The resemblance between the carpus andhand of our typical American monkey, andthat of the African, is still greater than thatof the arm and forearm. The scaphoid occu-pies an equally small portion of the wristjoint, and the os triquetrum occupies themost considerable portion ; the pisiform boneresembles a small calcaneum. There is anintermediate (ninth) bone, and the charac-teristic process of the unciform bone is

largely developed; the trapezoides penetratesless, or is more dorsal.*

* The description of the carpus of the

Sapajou, as given in the Systeme Anato-mique de Vicq-d’Azyr, in the " Encyclope-die Methodique," translated from the " Ana-tomie des Mammiferes," by Guilleim Joseph,is certainly wrong ; there are never more

than four carpal bones articulated with the

358

The bones which compose the hand re-semble, still more strongly, those of the P.Saboeus than even in the carpal region, ex-cept, perhaps, in their proportions ; thus, asa whole, the hand, including the fingers, islarger; the bones of the metacarpal regionare, on the contrary, shorter when comparedto the first phalanges, and the thumb a littlelonger, since it nearly equals in length thelittle finger, which is scarcely more slenderthan the others.The pelvic limbs, as I have already re-

marked, have a less proportion to the tho-racic limbs than in the P. Saboeus, and thisis sufficiently perceptible in each of its com-ponent parts.Thus the ilio-pubic semi-girdle, although

possessing the same form in almost all its

points, has, nevertheless, a shorter total

length, since from the anterior extremity ofthe ilium to the posterior extremity of theischium, the length only equals three-fourthsthe whole length of the femur, whilst, in theP. Saboeus it is the four-fifth. Anothermore palpable difference exists in the diverg-ing angle of the two branches of the ischium,which, although somewhat thicker, is not,however, spread out and enlarged like theischiatic tuberosity of the P. Saboeus ; this

peculiarity is common to all the family of theSapajous.The femur, proportionally, also, perhaps

a little shorter, differs only from that of theP. Saboeus in being a little straighter, thegreat trochanter not rising so high, and beingmore flattened.The tibia, about an eighth shorter than

the femur, whilst in the P. Saboeus thosetwo bones are equal, is, however, very similarto it, and the fibula is almost a perfectcounterpart to that of the Guenons ; perhapsthe malleoli are, however, a little more pro-jecting, and, consequently, the articulationcloser.The resemblance is traced on, in respect

to the proportions of parts, and for the bonesof the feet, nearly as far as those of the leg,excepting in slight differential shades, whichthe artist alone can show. Sometimes it hasappeared to me, that the tarsus of the C.Apella is a little more locked as it were,less flattened than in the P. Saboeus, and thegreat toe more opposable; and, indeed, thefoot is more similar to the hand, and propor-tionally shorter. In truth, that portion ofthe calcaneum posterior to the articulation,scarcely exceeds the half of the hand, whilstin the Magot (African Cynopithecus) it is alittle more than two-thirds.

All the skeletons or crania of the Sapa-jous, properly so called, which I have ex-

amined, have presented no ascending or de-scending differences in any of their compo-

five metacarpal bones, and there are alwaysfour bones in the proximal row of the car-pus.

nent parts ; * but this is not the case withsome of the sub-families, which zoologistshave arranged with the Primates (Cebid&oelig;)of America.

In ascending the scale, and thus follow.ing the plan which, upon deep reflection, wehave adopted, that is to say, passing fromthe C. Apella to the Ateles, Geoff. (Cebus,Erxleb. Simia, Linn) from the At&egrave;les to theSagouins (Callithrix, Geoff. Cuv. Illig,Cebus, Erxleb. Simia, Linn. Sagouins, La.cep.) ; and, lastly, from the Sagouins to theAlouates (Mycetes, Illig. Aluata, Lacep.Cebus, Erxleb. Stentou, Geoff. Simia, Linn.)or Harleur Simi&aelig;, we can observe some dif.ferences, although they do not at all indicatea gradation so well marked as in the Afri.can Simi&aelig;, from the Guenons, to the Chim.panz&eacute;e.The Ateles, or Sapajou, without the thumb,

(as the name Ateles, under which M. Geof.froy distinguishes them, indicates,) have, inthe more elongated general form of the head,a certain obliquity by the elevation of thecranium, which strikingly diminishes theextent of the facial angle by depressing theforehead.The snout is also a little longer, more

pointed, and the space between the orbitslarger; the orbits are less notched on theirexternal margin, and a little less lateralised.

The rest of the spinal column is verynearly, in all respects, similar to the C.Apella, only the dorsal vertebrae, which are,however, fourteen in number, have theirspinous processes larger, more approximat-ing to each other, and the two last directedobliquely from behind, although less so thanin the others.The lumbar vertebrae (only four instead

of five in number) are also weaker, and theirspinous processes much less oblique frombefore.The last of the three sacral vertebrae very

closely resembles the first coccygeal, its spi-nous process not even being included in themedian crest; and this, without doubt, hascaused Daubenton to state, that his speci-men of the At&egrave;les had only two sacralvertebrae ; but, in the specimen which is nowbefore me, the third sacral vertebra is cer.

tainly united with the other two, not onlywith the body, but with the transverse andarticular process, and even with the ilium.The coccygeal vertebrae are not only more

numerous, amounting to thirty-one, or, ac.cording to Daubenton, 33 instead of twenty-

* I find, however, that Daubenton statesthe skeleton of the Sai (S. Capucina) to havesix lumbar vertebr&aelig;, instead of five, as inour typical specimen; four sacral, instead ofthree ; and twenty-six coccygeal, instead oftwenty-two. This enumeration, giving nofewer than six additional vertebr&aelig;, if cor-

rectly given, will of course constitute a spe.cific,&mdash;an almost generic, distinction.

359

two, (as in the C. Apella) but the vertebrae cranon process, on the contrary, is thin andare generally longer. The first eight have a rounded.superior arch and transverse process, of The carpus, notwithstanding the rudimen-which the longest and most oblique belong tary state of the thumb, differs a little fromto a vertebra more posterior, the body of the that of the typical cebidae, that is to say, themore anterior vertebra being, at the same trapezium is at least as large as in the Sapa-time, shorter; the five last only, are pro- jous; the intermediate (ninth) bone is, per-vided with the V shaped bones, which haps, on the contrary, a little less.are of considerable size. Of the remaining The hand is also narrower and longercoccygeal vertebrae, the first has a mere than in the Sajou.rudiment of the V shaped bone; but, on the The bones of the metacarpus are the largestother hand, the articular processes of the of the three divisions composing the hand ;following vertebrae are very much developed. they are also much more delicate, and ap-The hyoid sternebra has its body in the proach, in length, much nearer the ordinary

form of a cuirasse, or breast-plate, very much proportions, only the first (that of the thumb)swollen out, like the bird’s sternum without is, perhaps, proportionally a little shorter;the brisket, being larger, and more bent it is, however, terminated by a small head.anteriorly than posteriorly, where it is also The proximal phalanges, four in number,narrow. (the thumb in no case having one) are one-The horns (appendages) which articulate fourth shorter than the metacarpal ; they

with the anterior and superior angles, are are likewise sufficiently enlarged and archedvery different from those of the C. Apella, towards their distal extremity, approachingindicating an animal more elevated in the in form that of the Gibbons and Orangs.scale; in a word, the anterior (styloid horns) The middle phalanges are also a little

are much shorter than the posterior, consist- more bent, and larger than in the C. Apella.ing of only one cartilaginous portion; the With regard to the distal phalanges, theyposterior (laryngeal) are rib-shaped, and are, on the contrary, shorter and more point-long. ed towards their termination.The sternebr&aelig; as a whole, and at the The four divisions of the posterior limbs,

same time in detail, as well the vertebral preserve, with an extremely similar form,as sternal appendages, are exceedingly like dimensions proportionally longer. Thus, thethose of the C. Apella, only all the por- ilium and ischium have a total length equal-tions of the thorax, and especially the ribs, ling thirteen of the dorsal vertebrae, insteadare evidently more slender, and the sterne- of eleven only, as in the C. Apella, the typebrae are flatter; there are certainly eight of comparison; the iliac bones, also, aresternebrae, as in the C. Apella. evidently longer, more fan-shaped, and

This delicacy shows itself still more in the rounded anteriorly.limbs, and in their various portions. The femur, which is only a little longerThe scapula, more oblique and particularly than the humerus, possesses, in other re-

small, since its whole length is to that of the spects, the usual form, only the great tro-humerus as 1 to 3, whilst in the Ateles it is chanter is not so strong, and a little moreas 12 to 21, showing (in the greater develop- elevated than in the Sapajous.ment of the tubercle at the root of the coro- The tibia and fibula have also preservedcoid process) an arrangement by which the the form and length of our type; they arefissure, on the anterior margin of the sea- only a little more delicate.pula, is converted into a hole, by the junction The foot preserves, also, its usual propor-of the terminal angle of that margin with the tions with respect to the leg. We maytubercle ; and, as the external (scapular) remark, however, that the astragalean part isend of the clavicle is evidenly very much a little more loose, less locked, the malleolienlarged, it follows that the articulation of being evidently less projecting. The meta-the clavicle with the scapula is effected, not tarsal bones which are a little longer, butonly through the acromion, but the corocoid especially more slender, decrease in lengthprocess. from the first to the last, with the exceptionThe humerus, whose length nearly equals of that of the great toe, which is shorter and

that of the dorsal and lumbar vertebrae, is, more set off at an angle.besides, remarkable for its delicacy, its The proximal phalanges preserve prettystraightness, the slight development of its nearly the same arrangement with regard tocrests and tuberosities, its thinning away size ; they are more arched than in the C.inferiorly, and the absence of a hole near Apella, a disposition which shows itself alsothe inner condyle,-most certainly a rather in the middle phalanges; the distal pha-peculiar difference. langes continue straight, and scarcely dilatedThe bones of the forearm are still longer, at their extremity.

almost equalling the entire vertebrae of the I have observed no other differences in thetrunk, but proportionally still more delicate osteography in the different species of thethan the humerus ; the radius is even slightly genus At&egrave;les, except that in the one which isbent, but the ulna is perfectly straight, and provided with a rudimentary thumb, we find,knife-shaped in its upper segment; the.ole- on the first metacarpal bone, a very small

360

phalanx, which supports the terminal pha-!lanx without a nail.The Sagouins (Callithrix Desm. Geoff.)

which appear to me still more closely toresemble the Alouates than the Ateles, re-tain, nevertheless, the proportions of the

Sajous, so far at least as I am able to judgeby their cranium, the only portion which Ipossess of their skeleton. iThe general character of the head is

similar to the Ateles, the forehead slopingrapidly backwards, the occipital bone andthe zygomatic arch being elevated in the samedirection; nevertheless, the facial angle isvery open (600) first on account of the ex- treme shortness of the snout (even greaterthan in the Sapajous), and then, owing to theextreme smallness of the frontal crests, whichgive to the face andforeheada subvertical line.In other respects, the inter-orbitar space, thezygomatic arch, and the malar foramen, arestill larger than in the Ateles; but there is novenous foramen behind the condyloid pro-cesses. The snout is at least as pointed, thenasal orifice is also of the form of a cloverleaf, and the angle of the lower jaw is muchlarger, more rounded, and even slightly ap-proaching the Alouates, and, unquestionably,for the same reason; lastly, the coronoid pro-cess is narrower, more elevated, and especi-ally more arched.The Alouates, including also the Eriodes,

which present merely a descending shadefrom the Ateles, enter, perhaps, more per-fectly, in certain respects, into the commontype than the Sagouins,, and even the Sapa-jous without the thumb.

The cranium and its appendages presenta more oblique arrangement, especially inthe aged males, which reduces the facialangle, until it does not exceed thirty de-grees, but we know that that effect is pro-duced by the development of the body of thehyoid, which necessitates a proportional de-velopment of the vertical branch of the lowerjaw; its angle, large and rounded, and conse-quently pushing upwards its condyle, and,following as a necessary consequence, theposterior part of the cranium, whose inferiorline is entirely turned upwards.*In addition, the face and forehead, also,

form nearly a straight line from the sinciputto the extremity of the incisive bones, andthe zygomatic arches, much larger than inthe other Sapajous, and not unlike the Sa-gouins, are parallel with the face and fore-head. The lower jaw is somewhat like abellows, so oblique and contracted is itsanterior extremity, and its inferior margin,

* Our author’s language in the precedingpassage must not be misunderstood. It isfor the purpose, no doubt, of giving brevityto the description that the term &deg; necessi-tates" is made use of.&mdash;R. K.

rounded, parallel to the extremely concavedentar edges, following the convexity of theupper jaw.*

All the characteristics of the crania in theother Cebidae, in other respects, reappear, inthat of the Alouates, only a little more deve.loped ; thus the inter-orbitar space, and themalar foramina, are greater even than in theAteles, and all the ridges, and depressions formuscular insertion, are much more fullydeveloped.

In respect to the other parts of the ske-leton, they altogether resemble those of theSajous, not only in number of pieces, in pro.portion, but even in the form of the variousportions.The cervical vertebra? have, nevertheless,

their spinous processes more raised and moredeveloped : these processes are also largerin the lumbar vertebrae, the transverse pro.cesses of the lumbar vertebrae being alsomore horizontal. The first of the lumbarvertebrae (five in all) as in the Sajou’s, has adelicate process, which might be consideredas a rib united to it, and which, in fact, islike a rib directed posteriorly.The three sacral vertebrx have their spi-

nous processes so large that they form acontinuous crest.

. The coccygeal vertebrae (thirty in number)are in other respects very similar to those ofthe At&egrave;les, not only with regard to the indivi-dual vertebra*, but also in the V shapedbones ; they are, however, generally and pro-portionally a little shorter.The hyoid sternebra (Figs. 40, 41, and

42,) of the Alouate Roux (C. Senicu.lus, Linn. Mono Colorado. Hmnb.) has longbeen remarkable for its very extraordinaryform ; in fact, with age, and especially inthe male, it is developed in the form of anenormouus oval bulb, oblique, and perforatedwith a large opening at its posterior base, asseen in Fig. 42, leading into an enormous

cavity, midway between the two rami of thelower jaw; the styloid horns, which havebecome very much depressed, the opening ofthe pouch being between the two pairs, arestill more rudimentary than in the At&egrave;le andSaki, so much so, indeed, that in the adultthey have altogether disappeared, a fact byno means so apparent in youth; the laryn-geal horns are, on the contrary, sufficientlylong to reach the superior angles of the thy-roid cartilage.

* Daubenton, xv., page 87, speaks of akind of articulation near the condyle, whichis not found in the other Cebidae, and isthought by him to be peculiar to the HowlingApes; but certainly the hyoid bone, howeverswollen it be, does not go so far as to giverise to such a joint, and this surface, whichthe celebrated colleague of Buffon took fora ajoint, is, unquestionably, the surface of inser.tion of the internal pterygoid muscle.

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Fig. 41. Fig. 40. Fig. 42.

Fig 40. Hyoid apparatus, viewed in profile ; 41, The same from above ; 42. The sameffom below.

The sternum is even shorter than in theSapajous ; besides, it is formed of only sixsternebras, including the xiphoid, which isvery slightly developed, and entirely cartila-ginous, which is also the case with the smallsternebr&aelig; belonging to the seventh andeighth ribs.The manubrium, or first portion of the

sternum, appears also more deeply notchedanteriorly than in the other Sapajous.The ribs are fourteen in number, eight ster-

nal, and six asternal, being the same as inthe Sajous ; but they are evidently a little lessthan in those animals, but not so delicate asin the Ateles.The proportion of the limbs is peculiar to

the group, the anterior are nearly equal tothe posterior; on the contrary, the posteriorare much longer in the Sajous, but they aremuch stronger, and not so delicate as in theAteles.The scapula is, perhaps, even still larger

than in the Sajous, especially in the greaterdevelopment of the fossa supra-spinata; theincrease in length of the anterior (cervical)margin, which runs gradually into the ante-rior and superior angle, and the prolonged,spatula-shaped, obliquely raised, basilar pro-cess of the coracoid.

The clavicle is, on the other hand, of adelicacy altogether remarkable, so as to formquite a contrast with the humerus ; it is,’moreover,, nearly straight.The humerus, nearly equalling in length

that of the femur, does not, nevertheless, quiteequal the fourteen dorsal vertebr&aelig;. It is,however, strong; its deltoid ridge is well-marked and sharp; there is no foramenin the internal condyle, as in the At&egrave;les,which, on the contrary, is present in theSapajous.

The forearm is proportionally still shorterthan in the Sajous ; in fact, the length of theradius is evidently less than that of thehumerus, the reverse of the arrangement inthe At&egrave;les; its form, and also that of the ulna,resembles greatly that of the Sajous ; the twobones being, however, proportionally a littlelonger, and more delicate.

The hand resembles the forearm, in beingintermediate between the Sajous and Ateles,resembling, however, more that of the Sajous,in consequence of the invariably constantexistence of a thumb ; but the proximal phalanges are stronger and, particularly, much

more arched than in the Sajous.The posterior limbs are extremely likethe anterior, although, proportionally, not solong.The pelvis presents only a few specific

differences; the same may be said of thefemur with regard to form; it is, nevertheless,a little longer in comparison to the bones ofthe leg, which, in every particular, resemble

those of the Sajou, only the external andinternal malleoli are not so prominent.The foot preserves, also, its resemblance as

well, generally, as in each constituent part,to the common type, Fig. 37.

Descending Scale.The osteographical differences are, per-

haps, better marked in the descending seriesfrom our common type.

All the remarks which we have just madeon the skeleton of the Alouates, may berigorously applied to the species of the

Cebid&aelig;, whose external characters haveled M. E. Geoffroy to distinguish it under thename of Lagothrix. (Lagotriche, Desm,Cebus, De Blain.) I may also just remarkthat in the skeleton of the Grison, in the

362

Museum, which was that of a young animal,the coracoid process of the scapula is dis-tinctly in the state of an epiphysis, a pecu-liarity which exists also in our skeleton ofthe young Chimpanzee, of Buffon, a factwhich I neglected to note in the descriptionof that animal.The Saimiris (Callithrix sciureus. Desm.

Geoff.) a small species of the Cebidae, inwhich the tail is entirely hairy, and scarcely,if at all, prehensile, still bears a strong re-semblance in its osteography to the Sajous;the head is only much longer, and as ifdrawn out superiorly, so that the externalauditory aperture is placed almost in themiddle of the whole length of the head, andthe occiput extends greatly behind the ver-tebral canal. The lower jaw is also muchlonger, and more depressed or less arched, inits vertical branch.But a peculiarity, which is proper to the

Saimiris, is, that the inter-orbitar septum isincomplete, by the absence of that bone,known by the name of the os planum (orbitarplate of the ethmoid in human anatomy); inother words, by the non-development of thelateral masses of the ethmoid, and also, thatthe entire cranium appears as if distended,the bones being extremely thin and loose,not only in their articulations, but in theirtexture. These two peculiarities, and moreespecially the incomplete state of the orbitarcavities, and the close approximation ofthe optic foramina, give the orbits somewhatthe appearance of those in Birds.* *The remainder of the skeleton does not ap-

pear to me to present differences of the leastimportance, at least so far as I am able tojudge from the inspection of the skeleton of ayoung animal, the only one in our collection.The number of the dorsal vertebrae is onlythirteen ; but there are seven lumbar, a

number which we shall find very generallypresent in the species terminating the series,and evidently leading towards the Carnivora.The lumbar vertebrae are also remarkablefor the antero-posterior direction of theirimbricated spinous and transverse processes.The sternum has seven sternebrae, with an

internal nucleus for the eighth; all thesesternebras are much flattened.

* What could Daubenton have meant,when he described the opening of the nostrilsin the Saimiris as being between the orbits, aswell, adds he, in the Gibbons and in theTalapoins? This is really what I cannotunderstand. The nasal aperture is of a tre-foil shape, or, perhaps, exhibiting fourrounded lobes, but it is not higher up than inthe Sapajous ! With respect to the littlebone which he describes, as placed betweenthe bones of the nose and frontal, this mustevidently be a supernumerary bone, and, inall probability, peculiar to the particularspecimen from which Daubenton drew hisdescription.

The ribs are thirteen in number, of whicheight are sternal and five asternal.The limbs are long and delicate.The scapula short, leaf-shaped, that is to

say, oval and equally convex on its twomargins.The humerus is perforated by a hole on

its inner condyle ; it is evidently consider.ably longer than the two bones of the fore-arm, which are exceedingly like those of theSajous. The intermediate carpal (ninth)bone is very small.The posterior limbs, much longer than

the anterior, have a very short ilio-ischiaticmeasurement; a femur one-fourth longerthan the humerus ; the tibia and fibula deli.cate, close, almost straight, nearly as long asthe femur; and the foot narrow, but equallingthe leg in length, is terminated by the nailbearing phalanges, which are, even stillmore pointed, than in the Sajous, and with.out depressed enlargements at their distalextremities.The Sakis (Cebus leucocephalus, Pithecia

leucocephala, Desma.) in whom the tail is ex.tremely supple, approaches, still less per.haps, the Sajous than the Saimiris, at leastinthe form of its cranium, for we observe thatthe arrangement of the incisive teeth in thelower jaw, resembles more that which occursin the Makis. The cranium, in its superioroutline, resembles also very much theSajou ;but the inferior outline is mueh less curvedat the sphenoidal junction, in such a waythat the occiput is slightly raised, resem-bling in a slight degree the arrangement ob.served in the Alouates, and, undoubtedly, forthe same cause, for the branches of the lowerjaw are very much dilated at their angle,and the zygomatic arch is a little oblique;there is no venous opening behind the con.dyles ; the jugal bone is rather small, andthe anterior opening of the inferior dentarcanal is almost as large as the jugal foramen.

Certain portions of the skeleton of theSakis approach, in their structure, the termi.nating species of the Sapajous, or the Micro-cebes, inasmuch as they have only twelvedorsal and seven lumbar vertebrae. Anotherremarkable peculiarity is, that as in theOuistiti, the body of the hyoid becomesagain of considerable size, its anterior hornsbeing reduced to minute cone-shaped carti-lages, the posterior horns being cask-shap-ed ; but this enlargement of the body of thehyoid is not in unison with the developmentof the branches of the lower jaw, which, inthis species, is determined by that of the thy-roid cartilage.The internal condyle of the humerus is

perforated with a hole, as in most of theSapajous.The Douroucouli (Cebus Trivii-gatus), a

small nocturnal species of the Cebidae, re-sembles the Sagouins, in many points of thestructure of the cranium; but the remainder

363of its skeleton has evidently a much greaterresemblance to the Saimiris.

The head, as a whole, resembles, slightly,that of certain small species of Makis, bythe great extent of the orbits, and even thatof the cat tribe, or pure Carnivora, by thecontinued arch of the frontal and nasalbones, the nasal openings being subterminal ;the cranial vault, slightly elongated, extends ’,posteriorly considerably beyond the occi-pital foramen, and the snout is excessivelyshort, the zygomatic arch is delicate andoblique, the external orbitar foramina arevery small, and two in number; the sphe- Inoidal fissure is very large; the coronoid ’,,process of the lower jaw is evidently much I,more elevated than in the Sajous, and more ’’,resembling that of the Sagouins. IThe skeleton of the Douroucouli (of

which we possess a perfectly complete inatural skeleton, made under our ownimmediate inspection, and from a speci- Imen which has been drawn by Mr. Fred.Cuvier) has fourteen dorsal vertebrae, withthe spinous processes nearly resemblingthose of the Sajou; but the lumbar region,greatly elongated, is composed of eight ver-tebrae, increasing in dimensions, very evi-dently, from the anterior to the posterior, as Iwell in their bodies as in their spinous andtransverse processes, more epecially the last, !,their transverse processes being directed very imuch forward. The sacrum has three ver-tebras, united even by their spinous pro-cesses ; and the tail,’ of which the first fourvertebras only are complete, is composedmost certainly of no more than twenty ver-tebrae, and these all elongated and unequal;the V-shaped bones are of small size, andconnected with the first four or five coccy-geal vertebrae only.The sternum has its eight sterneba3 well

formed.The ribs, fourteen in number, of which

the nine sternal are large, flat, and verythin ; their cartilaginous portion is long andnarrow.

The limbs and their component partsresemble, strongly, in their proportions andform, those which we have just described inthe Saimiris.The scapula, however, is proportionally

larger, equalling two-thirds of the humerus,whilst it scarcely exceeds the half in theSaimiris; the humerus, also, is perforatedwith a short canal on its internal condyle.The two bones of the forearm are proportion-ally longer.The ilio-ischiatic measurement is only a

little shorter than in the Saimiris ; but thethigh, leg, and foot, present scarcely anyappreciable differences, except to the artist.

Lastly, the terminating species of theCebidse, or American Monkeys, compre-hends the Tamarins and the Ouistitis, in

which the great toe is no longer opposable,and the nails have the form of claws.*

In all the smaller sized Cebidae, the gene-ral form of the head bears the strongestresemblance to that of the Saimiris and theDouroucoulis, by the more or less elongated

* We feel inclined to except the distalphalanx of the great toe, which, most

assuredly, still retains its flattened form,and in the stuffed specimens we have seen,the horny envelope invariably appearedmore like a nail than a claw. We find thisfeature most distinctly marked in a speci-men of a natural skeleton of the Ouistitis inour own private Museum. The specimenwas kindly presented to us by Sir JamesRobisson, and prepared.by Mr. Fred. Knox,with great care. We add the followingmeasurements and observations on this spe-cimen, seeing they are so rare in Britain :-

It will be observed, that the lower jawhas two molars more than the upper, andthefourth molar (counting from before back-wards) is by much the largest; it has fourtubercles, two on the external margin, twoon the internal margin, the posterior internaltubercle being much smaller than the others.In the upper jaw. where we have two teethfewer than in the lower, it appears to us byno means easy to determine which of theteeth are wanting, at all events, from theirexternal appearance as placed in the jaws.The teeth wanting, however, must either bemolars or canine, and it appears to us thatthey are the canine teeth which have not cut,seeing that the large molars analagous to

364

form of the cranium, and especially by theshortness of the snout, insomuch that thefacial angle might safely be considered asaveraging 50&deg;, the forehead and face be,coming vertical ; the plane of the orbits ievery slightly oblique, that of the nostrils islikewise nearly vertical, the nasal bones artparallelogramic, instead of being triangular ;lastly, the angle of the lower jaw assume!more the form of a process.The rest of the skeleton preserves also the

same characters; the anteriorlimbs, howeverare, perhaps, still shorter in comparison thanthe posterior.The number of the dorsal vertebrae de.

creases to twelve, although there may, al

times, be thirteen, as in the Ouistiti ; andwhen there are thirteen dorsal, the lumbawill be only six, instead of seven, which isthe most usual arrangement. The spinousand transverse processes are long, and lookor point from before backwards. The sacralvertebras are often two, but sometimesthree, in number, but the first only articulates with the iliac bones. With regard tcthe coccygeal vertebrae, they are sometimes,when the tail is very perfect, twenty-eighlor thirty in number ; they are of the usualform and proportions.

It is worthy of remark, that the hyoidapparatus has still its body large, but withoulthe cavity (as in that of the Alouate RouxFig. 40, and particularly that the styloidhorns are, again, reduced to an extremel)small tuberculous point, and inacartilaginousstate, situated at the base of the laryngealhorns, which are very large, having someresemblance even to the first ribs in man.The sternum is never formed of more than

seven sternebrae, including the two terminal’;they are large and flat, but in the Ouistitithey are only six in number, the sternebrabetween the fifth and terminal (xiphoid)not having ossified.The ribs, twelve in number (rarely thirteen,

as in the Ouistiti), are still large and flat,with the exception of the last, which isstraight and delicate.The anterior limbs, shorter as a whole,

and also in each particular division, have, in

those in the lower jaw, are distinctly pre-sent. If we are correct, the permanentcanines in the upper jaw have not appeared,and there is no apparent space for them inthe jaw, although those in the lower jaware of considerable size, although evidentlyrecently cut.

It seems sufficiently curious, and ex-

tremely interesting to observe, that the den-tition, as we approach the lowest terminusof the -Quadrumana, or the last of the Cebi-dae (American Monkeys) appears to returnto that type, persistant and characteristic inthe Simiae, or African Monkeys, and whichwe have seen so closely to approach thenuman organisation.&mdash;R: Knox,

other respects, an almost perfect resemblaneewith those of the Sajous ; the same form ofscapula, clavicle, humerus, whose innercondyle in the Tamarin is even perforatedwith a short canal, which, however, is notthe case in the Pinche, nor Ouistiti; thesimilarity still continues with regard to theradius, ulna, and carpal bones, metacarpal,and fingers; the intermediate (ninth) boneof the carpus is even proportionally a littlelarger than in the Sajous, the trapeziumbeing, on the contrary, evidently smaller;but the distal phalanges, including even thatof the thumb differ, especially in being short,straight, compressed, and delicate.With regard to the posterior limbs, the

pelvis differs slightly from that of theSajous, inasmuch as it forms a more obtuseangle with the vertebral column, articu.lating, in fact, with only one sacral vertebra.The iliac bones are also, perhaps, a littlenarrower.

In respect to the femur, tibia, and fibula,I found no differences worthy of remark;and I may say the same with regard to thefoot, with the exception of the tuberosity ofthe calcaneum, which is considerably morepulley-shaped, and the distal phalanges,which resemble those of the fingers.

SESAMOID BONES.

The number and arrangement of the oste.ides, or sesamoid bones, do not appear tome to differ much from those of the Simia;,or African Monkeys.

I( In the anterior limbs, we find the sesa.moid belonging to the tendon of the abductorlongus pollicis. I have not found that of theflexor carpi ulnaris, and even Daubentondoes not appear to have been more fortunatein finding it; in fact, the carpal boues, in-cluding the osteides, in the Cebid&aelig; never

exceed ten in number.The sesamoid bones, belonging to the

tendons of the perforating flexor muscle,are extremely minute.In the posterior limbs, the rotula is oval,

large, subhexagonal in the Sajous, and inthe other ascending species ; but in the de.scending species it became narrower andregularly oval.The sesamoid bones, developed in the

tendons of the gastrocnemii muscles, are

pisiform, and large ; that of the popliteusmuscle does not appear to me to be presentin the Sajou ; in a young At&egrave;le it was ex-tremely small and flat.

In the foot, we find the sesamoid of theabductor of the great toe; of the long pero-neal muscle ; that in the tendon of the flexorof the great toe of considerable size, andthose in the short flexor of the other toesextremely small.

OF THE TEETH (Phanerostea).The system of dentition in the Cebida;, or

American Apes, resembles, in many respects)

365

in its general arrangement, that of the Simiae, however, consists in their having an addi-

not only in their general form, but in the tional (anierior ?) molar.number of the three sorts of teeth which The incisive teeth in the Cebus Apella,.constitutesthe system ; the chief difference, our typical specimen, are in general smaller,

Fig. 43.

Fig. 44.Fig. 43. Upper jaw, right side, dentar aspect; 44. Lower jaw, right side, dentar aspect.

shorter, more transverse, than in the typical obliquely in the upper; nearly round in theSimiae (Pithecus Sub&oelig;us), and more especi- lower jaw. Of the four tubercles whichally the first pair of the upper jaw, can the corona presents, two are reunited by ascarcely be distinguished from the second. transverse ridge, the posterior tubercles inThe canines are, also, generally not so the last tooth of the upper jaw, the anterior

strong, less sloping ; nevertheless, in the in the last tooth of the lower jaw.male adult, they are thick, strong, sloping The arrangement, which we have justoutwards; those in the upper jaw very described as existing in our typical Apella,distaatfromthe incisors, grooved and cutting; is the same in all the ascending series, withthe canine teeth in the lower jaw, smoother very slight modifications.and crotchet-shaped. In the Ateles (Atele Belzebuth. C. Brisso-The molar teeth, in both jaws, commence nii), for example, we observe this difference,

in close connection with the canines ; they viz., that the incisives are much larger, moreare also very close to each other; there are cutting, and arranged more in a circle.three anterior molars, one principal molar, The canines, and generally all the molars,and two posterior molars. are, on the contrary, much smaller; theThe three anterior molars are transverse molars are also rounder, and the tubercles

both in the upper and lower jaw, that is to on their coron&aelig; are less marked, less ridged.say, their transverse measurement is greater The three anterior decrease from the first tothan their horizontal, and consist, as it were, the last, as in the Sapajou ; but in the lowerof two parts, one external the other internal ; jaw, the intermediate molar is a littlethose in the upper jaw being unequal, the stronger than the first, and the posteriorinternal division of the tooth having the molars in both jaws have, in the form ofform of a heel, but those parts are equal their posterior divisions, something whichin those of the lower jaw, and are united by indicates an approach to the structure of thea transverse ridge, with the exception of the Gibbons.first tooth, wLich is evidently much stronger, The Sagouins (Callithrix, Geoff.) haveand the external point of which is increased an arrangement of their dentar system whichby a small anterior tubercle. slightly approaches that of man, chiefly be-Of the three remaining molars, the first or cause the teeth are almost all of equal height ;

principal is the strongest, both in the upper the canines being extremely short, and the in-and lower jaw ; less square, or more trans- cisives, also, are implanted vertically in theverse in the lower jaw than in the upper; jaws. The first superior incisors are, in the.the terminating tooth of the series is evi- meantime, proportionally much larger thandently the smallest; it is oval, and placed in the Sapajou. The canine teeth, and

366

more especially those of the lower jaw, Iscarcely pasx beyond the others. The molarsof the upper jaw increase regularly from thefirst to the last but one, which is nearly ofthe same size and of an oval form. The firstfive have a large tubercle internally furrowedwith two crescents, and one or two smalltubercles externally, according as they areanterior molars or not. The six molars inthe lower jaw increase regularly from thefirst to the last inclusive ; but this letter is alittle narrower than the one before it.

In the Alouates (C. Seniculus, StentorSeniculus, Geoff. Simia Seniculus, Linn.) theincisives and canines, again, become verymuch as they are in the Sapajous, the in-cisives being small, nearly equal, and trans-verse ; the canines being sufficiently long,crossed, and diverging ; the molars resem-ble those of the Sagouins, only both in theupper and lower jaw the last molar is,proportionally, still a little stronger, by theenlargement of its keel, which is, neverthe-less, slightly less marked in the CebusArachnoides (At&egrave;le Arachnoide. Desm. Geoff.typical of the genus Eriode of Geoff.) andwhich, as well on this account as owing tothe shortness of the thumb, forms an ap-proach towards the Ateles. In the Alouatesthe tubercles of the corona of the posteriormolars, are also more complex than in theSapajous; in fact, superiorly, the principalmolar more especially, is edged externallywith an anterior external tubercle, and twointernal ones ; and (of these two, the anteriorlarger than the posterior, wears away intoa crescent-shaped surface; and in the lowerjaw, this wearing away, acting upon thetwo pairs of tubercles, produces two ob-liquely transverse crescents, the anterioroften more elevated than the posterior.

If we now proceed to examine minutelythe dentar system of the Cebidae, in thedescending series, we shall find, in the firstplace, in those in whom there are still sixmolars, that is to say, in the Saimiris (C.Sciureus, Sagoin Saimiris, Callithrix sciureus,Desm. Simiu sciurea, Linn.) the arrange-ment and proportion of the incisors, of thecanine, and even the molars, resembles thatof our typical specimen ; perhaps, however,the last molars, as well in the upper as inthe lower jaw, are still smaller in them ; but,assuredly, the sharp and hollow parts of thecorona are more marked, more insectivorousor cutting.In the Sakis (C. Leucocephalus. Pithecia

leucocephala, Desm. Geoff. Sim&iuml;a pithecia,Linn.) the molar and canine teeth are as inthe Sapajous; but the incisors are muchmore inclined outwards, particularly thosein the lower jaw, where they are long, nar-row, converging, almost as in the Makis

(lemur.)Lastly, in the few species in which there

are only five molars on each side of eachjaw.

The Tamarins, (Ouistiti, Midas, Desm.Geoff.) which commence the descendingseries, have the incisors, the canines, andeven the anterior molars, as in the Sapajous,and especially as in the Saimiri ; but theprincipal and posterior molars approach inform and proportions those of the two pos.terior molars in the Sapajou, indicating, toall appearance, that it is the principalmolar which is wanting.

In the Ouistiti, which have the samenumber of molar teeth, it would rather ap.pear that it was the last molar which haddisappeared, because the third of the seriesis larger and has four tubercles. But thegreat distinctive marks, which we observe,are in the length and narrowness of the in.cisors of the lower jaw, which, differing butslightly from the canine, are, like them,directed forwards, like the teeth of a comb.*

Of the Alveoli.After what we have just said of the

corona in the dentar system of the Cebidas,we can readily perceive that the roots, andconsequently the alveoli, must present nogreat complexity.

Fig. 45.

Upper jaw, right side, dentar aspect, withthe teeth removed, and represented so as toshow the alveoli and the fangs of the teeth.

* In so far as we can observe, M. DeBlainville has not given any positive datato determine which of the series shall beconsidered as the principal molar. If wetahe as a character the size of the tooth,and man as a type of comparison, then itwould appear that in the Ouistiti (whoseteeth in regard to number are similar toman) there is a posterior molar less and ananterior molar more than in man. We havealways considered the first permanent molar(in fact the first of the permanent teeth) inman, as the principal molar. Now, notwith-

367

Fig. 46.

Lower jaw, right side, dentar aspect, with the teeth removed, and represented so as toshow the alveoli and the fangs of the teeth.

In the Cebus Appella, in fact, the inci-sors and canines have, invariably, a suit ofroots, long and conical, which also indicatethe form of the alveoli. The anterior molarshave, like their coronas, their roots com-

pressed, forming two roots, more or lessintimately united at their base, and diverg-ing at their summit, which gives to thealveoli the form of a keyhole, instead of threeholes in a triangle, which we have seen inthe alveoli in the upper jaw of the Simia(see Fig. 33, p. 325) ; and with regard to theprincipal and posterior molars, their rootsand the alveoli also resemble, in a slightdegree, those of the Simiae. In truth, inthe upper jaw for the three first molars,there are three oblique alveolar holes, twoof them small, very close together exter-nally, often -running together at the en-

trance, and a larger one internally; theteeth have also their three roots, two ex-ternally, diverging, and one root internally,which, however, is by much the strongest.The last molar has only one compressedroot, corresponding to one oval and obliquealveolar cavity.

In the lower jaw (Fig.46,) the arrangementof the dentar system and their alveoli issimilar to that of the Simiae, only, the threeanterior molars have their roots simple; thatof the first being much longer than theothers, in which it is also more tetragonal ;we have thus three alveoli-like keyholes,one for each tooth. The principal and firstposterior molars, as well as their alveoli,are thus sufficiently similar to those of theSimix, having two compressed roots, diverg-ing, and a double alveolus, like a keyhole ;but the last posterior molar is always cha.

standing M. De Blainville’s extensive op-portunities and scientific accuracy in allthings, he does not appear to have deter-mined, from observation, whether the firstcut permanent molars in the Primates arethe largestr. Knox.

racteristic, its root being single, conical, andimplanted, in a nearly circular alveolus.

In comparing with what we have justseen in the Cebus Apella, the ascendingspecies, that is, the Ateles (C. Brissonii),the Sagouins (C. Apella) and the Alouates(C. Siniculus), we have observed no otherdifferences than in the proportion of the root,and of the alveolus of the last molar tooth,as well in the upper as in the lower jaw,and even that difference is very slightlymarked ; and only in the Sagouins with re-gard to the last molar in the lower jaw,which has two roots and only one alveolus,and especially in the Alouates, where thatpeculiarity is generally present in the upperjaw. In respect to the Allies, all the dif-ference which they present, as comparedwith the Sapajous, is in the more rounded,more closely arranged, form of the root andalveoli.The first species of the Cebidae, in the

descending scale from our type, have theroots of their teeth, and the alveoli, perfectlysimilar to the Sajons; but it is not preciselyso in the Microcebes or Ouistitis. Never-theless, in all the lesser species, the diffe-rence is not observed, in the first three

I molars, which have always only one root andone alveolus like a keyhole ; but the fourthmolar of the upper jaw has three roots, andtheir alveoli slightly separated, and that ofthe last molar, both in the upper and lowerjaw, are simple, which gives rise to thebelief that in the Ouistiti it is the absenceof the principal molar which constitutesessentially the difference in their dentarsystem from that of the Sapajous.

G"owtk of the Teeth. -

, I have not, unfortunately, in so perfect amanner, as in the case of the Simiae, theproper elements to determine the changeswhich age produces on the dentar systemof the Cebidw ; I consider, nevertheless, asII A First Epoch that state which I have ob-

368

served in a young specimen of the Chamek(C. pentadactylus, Atele pentadactylus, Geoff’,)The incisors are vertical, very small, looselyplaced (not close) in a shorter oval palatinesurface, in other respects not unlike thoseof the adult; the canines resemble the firstanterior molars of the adult, with an anglemore developed. With respect to the

molars, there are already three, two anterior,and the principal molar, making in all 24teeth. Thus, in the,first epoch, the Cebidaediffer from the Simiae in having an addi-tional molar.* In the same epoch a Sajouhas the incisives, and especially the canines,much stronger; and a specimen of theOuistiti, at about 37 days after birth, hasthe incisors very much developed, with thecanines, on the other hand, smaller than thetwo first molars; and the third molar has itsanterior tubercle just cut. Thus, there is

only an extremely short period of time inwhich the two first molars are alone present.

In thesecond Epoch, with the incisives re-placed by permanent, and the canines deci-duous, 3 molars exist, as in the first epoch,which, in respect to number, resemblesthe arrangement in the Simiae or AfricanApes; the first molar,evidently much smallerthan the second, and the last much stronger,with three roots in the upper, and two inthe lower jaw. This epoch, then, has 24

teeth, as in the first epoch; it appears thesame in those Cebidae, with the six molarteeth, as well as those with five. I have,in fact, observed it to persist in the At&egrave;le,in the Sanmiri, and in the Ouistiti, and bysure induction in the Alouate and Tamarin.

It is nearly the same with regard to theThird Epoch, in which everything resemblesstrongly that of the second, with the differ-ence, that there is an additional molar; thusmaking, with the three of the first epoch,four in all on each side of each jaw ; that is28 teeth in all. I have observed this condi-tion in a young Alouate roux (C. Seniculus,Simia Seniculus, Linn), and in. a Tamarin(Ouistiti, JJ1 idas, Geoff.)The Fourth Epoch, of which I have seen

Our readers will, by referring to ournote on page 366, see how desirable it wouldhave been to have given a fixity of charac-ter to the so-named principal molar. Thecondition of the teeth in this specimen,is evidently strictly analogous to that ofthe child, when he has all his deciduousteeth still in the jaw, with his four perma-nent molars additional, the total number inboth jaws being then 24, of which 20 aredeciduous. Our author appears to us tohave erred, in using the term principal, toany tooth of the deciduous series. The

term, in our opinion, would have been muchbetter preserved for that permanent molarwhich is first cut, without any reference tothe size of the tooth.-R. Kiiox-

an example in an Alouate noir (Alouatecar&middot;aa, stentor niger, Desm. Geoff.) and in aspecimen of the Ouistiti. In this conditionof the dentar system there are, together withthe three molar teeth of the first epoch, asin the two preceding epochs (2 and 3), two,or one permanent molar, which brings thenumber of molars present to five in the Alon-ate, 32 in all, or to four in the Ouistiti, 28in all, the last molar being wanting in theOuistiti. It is in this, the fourth epoch,that the change of the deciduous molarstakes place by the successive throwing offof each of them. The first of the deciduous,the smallest being replaced by the largestpermanent ; the second deciduous, by a

second of the permanent; and, the lastdeciduous, by the third permanent molar.This arrangement, I have observed, in a

satisfactory manner on a head of the Alouatenoir (stentor nigen, Geoff.), in the collectionin the Museum.In respect to a Fifth Epoch, there are,

then, still the same number of teeth as inthe 4th epoch, but they are all permanent,and there remains only to complete thedentar system, the (cutting of the lastmolars, which precedes, or, without doubt,immediately follows the change of thecanine teeth as in the Simiae; in the onecase making 34 permanent teeth, and in theother, 32. I have observed the first condi.tion in a young Sapajou grison (C. Griseus,Stiioit Gris, Buff. Cebus Bai-batus, Geofr.)The result of trituration on the molar

teeth in the Cebidae is thus very similar tothat of Simise, commencing on the principal;the effects decrease from behind forwards,in regard to the anterior molars, and frombefore backwards, with respect to the poste-7-ior molars, which is in the order of theiroriginal appearance.

ENDEROSTEA.

The other hard parts, which enter intothe organisation of the Cebidae, are limitedas in the Simiae to the bone of the penis(enderos), which is also extremely small, sub-cylindrical, evidently curved towards itsfree extremity ; in the Cebus Apella, ourtypical specimen, it only equals 4! lines inlength.

INOCULATION OF SMALL-pox.&mdash;Dr.Corbett,of Innishannon, Ireland, writes, "the mis-chief accruing from itine7’ant inoculationsin this country is truly shocking, and fornearly eighteen years, in which I have beenin practice in an extensive district, I havenever known variola to make its appearance,excepting after the visit of the inoculator.At this moment, small-pox is raging here toa great extent, and I have traced its intro.duction to the itinerant."