PHYLUM CHORDATA THREE COMMON CHARACTERISTICS I. NOTOCHORD; a cartilage support rod sometime during development. II. DORSAL NERVE CORD ;central nerve or ‘spinal’ cord along the back. III. PHARYNGEAL GILL SLITS; Pharynx=throat region, some time during development (embryo)

SUBPHYLUM UROCHORDATA CLASS ASCIDIA; Sea squirts sessile filter feeders on dock floats and dock pilings. CLASS THALIACEA; Tunicates colonial, sessile and pelagic filter feeders Salps, pelagic, transparent barrel shaped filter feeders.

SUBPHYLUM CEPHALOCHORDATA LANCELETS; Amphioxus, small fish like ancestors of vertebrates. Filter feeders living in sandy bottoms.

SUBPHYLUM VERTEBRATA THE VERTEBRATES VERTEBRAL COLUMN of bone or cartilage. SKULL enclosing brain etc.

CLASS AGNATHA The Jawless Fishes LAMPREYS; salt and freshwater parasites on other fishes. HAGFISH; deeper water scvengers and parasites.

Lamprey