Phylum priapulida

by:Jessa Mercado

Grace Ormeneta

Cactus Worms or Penis Worms

Etymology

From the mythical god, Priapos, who

symbolized the regenerating power

of the male gender

Fossil RecordOttoia Prolifica - a primitive

Priapulid worm- Burgess Shale - lived in a U-

shaped burrow that is constructed in the substrate

Characteristics 17 living species &

11 fossil species 0.5mm to 300mm

long Small, yellow or

brown, cylindrical worm

carnivorous worms

Characteristics Bilaterally

symmetrical and vermiform

Coelomate or pseudocoelomate

Complete gut with mouth and anus

Characteristics Sexual and

gonochoristic Feed on other

marine worms Marine and benthic unsegmented

Organ SystemsRespiratory System mostly none haemerythin

Excretory System excretion via protonephridia

Organ Systems

Circulatory System none but contraction of body wall

circulate fluids in body cavity fluid contains blood cells and

phagocytes

Organ Systems

Nervous System contains several ganglia the cord governing the nervous

system runs down the front area of the body (mid-ventral)

Organ SystemsDigestive System complete digestive tract feed on soft bodied inverts such as

sand worms, bacteria and other microorganisms

some species are suspension feeders

contains microvilli to improve absorption

Reproduction separate sexes and there is

normally only one ovary or testis external fertilization the larvae form of cactus worms are

protected by cuticle plates as they grow

undergo several moltings free swimming larva

Body PlanDivided into three

body regions:

Head

Trunk

Caudal

appendages

trunk

Body PlanHead/Proboscis locomotion &

feeding has adhesive

tubules used to capture prey

has scalids surrounding the mouth

trunk

Body PlanTrunk covered with

tubercles and spines

30-100 superficial rings

trunk

Body PlanCaudal

Appendages hollow probably a

respiratory organ also

chemoreceptor

trunk

Body Plan

Body Plan the epidermis is supported by

circular and longitudinal muscles which lies within it

coelom acts as a hydrostatic skeleton

Did you know?

Priapulids have great difficulty burrowing back into the mud after getting unattached.

SpeciesPriapulus caudatus

SpeciesPriapulopsis bicaudatus

SpeciesHalicryptus spinulusos

Life Cycle