Squid is a popular name applied to numerous marine mollusks, belonging to the class Cephalopoda, which also includes the cuttlefish and octopus. The squid has ten arms, a horny pen, the remnant of a shell, and a cornea closing the eye. The body is long, pointed behind, and bears two triangular posterior fins. The skin round the mouth bears suckers; the two longest seizing-arms bear four or more rows of suckers, and are not entirely retractile; one of the shorter arms becomes much modified in the male to form a "hectocotylus" or sperm-holding organ.
Ordinary squids are from 1 to 2 feet in length. The largest squid known is
Architeuthis princeps, nearly 19 feet long in body; the longer arms measure about 29 feet, the entire animal, with extended arms, reaching a length of 40 feet. Another species,
A. monachus, has a body about 7 feet long, with the two longer arms 24 feet in length. Flying squids are oceanic decapods of the genus
Omnostrephes.
