branchinks (Mussels, Cooklon, Oysters).

insteropods Cephalopoda (Cuttle Fishes).

Sub-class.

Branchiogasteropoda (Whelka, Periwinkles, Sea Slugs). Pulmogasteropoda (Slugs, Snails).

Pheropoda ("Butterflies of the deep ").

DROMAL ATARGET AND PHYSIOLOGY.

IENCE.