Deuterostomate Animals Embryonic blastopore becomes the anus. Three body layers. True coelom. Dorsal nerve cord.

Echinodermata Spiny exterior Calcified internal skeleton Bilateral symmetry in larvae, but often radial symmetry in adults Water vascular system for mobility, gas exchange, and feeding. system of internal tubes and canals tube feet that can exert strong suction

Phylum Chordata Pharyngeal slits (gill slits in neck) Hollow dorsal nerve cord Ventral heart Post-anal tail Dorsal supporting rod, the notochord Many of these may become obscure or absent in later development of the organism.

Invertebrate Chordates Tunicates – tadpole-like larva has chordate features; adults are sessile Lancelets – notochord throughout life

Vertebrates Notochord replaced by vertebral column two pairs of appendiages anterior skull well-developed circulatory system closed system (blood leaves heart and returns to heart in closed vessels)