Squid Squid Squid are cephalopods in the order Teuthida with elongated bodies, large eyes, eight arms and two tentacles. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin. Squid can change colour for camouflage and signalling. Some species are bioluminescent, using their light for counter-illumination camouflage. Squid are members of the class Cephalopoda, subclass Coleoidea. The squid orders Myopsida and Oegopsida are in the superorder Decapodiformes (from the Greek for "ten-legged"). Two
Bathyteuthis abyssicola without free trabeculae (beam- or finger-like protuberances). Suckers are relatively few in number, about 100 on each of the upper six arms (pairs I–III). Sucker rings on the arms have 8–18 separated, bluntly rounded to truncate protuberances. The tentacles and clubs are relatively short. Gills are short and narrow. They have large photosensitive vesicles just behind the eyes which appear to detect bioluminescence. These photosensitive vesicles are among the largest known in any cephalopod. Bathyteuthis abyssicola Bathyteuthis abyssicola, also known as the deepsea squid, is a species of squid in the family Bathyteuthidae. "Bathyteuthis abyssicola" is the type species of