Lecture—3 October 2003

Another deuterostome

Chaetognatha

Small planktonic carnivores

Often associated with major water masses

Limited variability in body plan

Chitinous bristles around mouth.

Protostomes

Ecdysozoa

Aschelminthian

Cuticle

False body cavity

Usually have a constant cell number

Nematodes—round worms

Extremely important group

Rotifers

Important part of the plankton

They show parthenogenesis

They have spines--cyclomorphosis

Acanthocephalans

Gastrotrichs