The most obvious difference between most cephalopods and other mollusks is the apparent lack of a shell. Octopuses do not have shells at all, while squids have a small internal shell. Cephalopods have a more developed nervous system than other mollusks. They also have very well developed eyesight that is used in finding prey. Once prey is found, it is grasped firmly and eaten with a mouth located at the base of the arms.
Cephalopods also have a parrot-like beak which is used in biting into prey.
An octopus has eight arms. These extra two arms are called tentacles. The arms of both squids and octopuses have suckers on them used to latch onto prey. All rights reserved. The Evergreen Project, Inc.