Phylum Platyhelminthes - Phylum Brachiopoda

Marine “Worms” and False Clams

Phylum Platyhelminthesincludes flatworms, tapeworms and flukes

bilateral symmetry

body flattened dorsoventrally (back and front)

Class Turbellaria: marine flatworms

not parasitic

move by cilia and/or slime trail

found in benthic habitats

have Ocelli (light sensitive eyespots)

can regenerate!!!

Very Strange ReproductionPenis Fencing

Phylum Nemertinaincludes ribbon worms

small, inconspicuous worms

live in shallow water, benthic environments, often found in mussel beds

complete digestive tract - first animal with mouth and anus

have a proboscis - for defense and gathering food

elastic worms can stretch, but break into pieces with the slightest disturbance - can regenerate

Phylum AnnelidaBilateral Symmetry

Closed Circulatory System!!!

Have Segments - internal and external

Each segment has Parapodia (used for crawling, swimming, anchoring in tubes)

also have Setae - bristles used for locomotion

allows for “peristalic contractions”

Phylum AnnelidaClass Polychaeta

marine worms

can be pelagic - enlarged parapodia for swimming (Errant Polychaetes)

can be benthic and crawl

can be sessile - live in tubes (Sedentary Polychaetes)

some are commensal and live within other organisms-sea stars, limpets

can be filter feeders or aggressive predators with a proboscis

Phylum AnnelidaErrant Polychaete examples:

Nereis: Clam Worm

can be 30-40 cm long

live in mucus lined burrows near low tide

seizes prey through jaws which are pushed through mouth via the pharynx - think “Alien”

Phylum Annelida

Fire Worms

hollow Setae with poisonous secretion

when touched setae break off and cause irritation

Scale Worms

flattened bodies

carnivores

More Errant examples