Unit 10 - Nematoda, Onychophora, and Tardigrades

Nematoda and Anthropoda

Tougher cuticle made of chitin

growth, cuticle, ecdysis

Free living and parasitic

Elongated, cylindrical, tapered at both ends, pseudocoelomate, hydrostatic skeleton, No motile cilia or flagella, Thick cuticle of collagen layers.

Longitudinal layer of muscle (No circular layer)

Muscle cells extend a process to the neurons.

Simple and complete alimentary canal, muscular pharynx, non-muscular intestine.

No specialized circulatory and resiratory structures, hemolymph in hemocoel circulates nurtrients out from gut and gases in from body wall.

No cilia or flagella, no flame cells, no protonephridia. Nitrogenous waste diffuses across body wall.

Achieved by unique gland cells and/or canal cells that empty via an excretory pore.

Gonochoristic, Males are smaller than females and have a curved posterior, amoeboid sperm, fertilization is internal, eggs stored in uterus.

Simple brain with a nerve ring around the pharynx, 4 nerve cords, dorsal ventral and lateral on each side. Dorsal and ventral control the body wall muscles.

Caenorhabditis elegans, first animal to have complete genome sequenced.

Ascaris lumbricoides

Enterobius vermicularis

Trichnella spiralis

Dirofilaria immits