They are often confused with arms -- octopuses have eight arms, while squid and cuttlefish have eight arms and two tentacles.
en.wikipedia.org Many cephalopods including octopus, cuttlefish, and squid similarly use colour change, in their case both for camouflage and signalling.
en.wikipedia.org They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.
en.wikipedia.org In most cephalopods, such as octopus, squid, and cuttlefish, the hyponome is a muscular tube.
en.wikipedia.org Surveys indicated that the cuttlefish biomass remained stable from 1998 to 2001.
en.wikipedia.org