How are the tentacles and arms of a squid different?
Squids have 10 appendages, 8 arms and 2 tentacles. These vary slightly in appearance and in use.
The two long tentacles have suckers (the small round disks most cephalapods use to grasp surfaces and prey) only on the end creating a sort of hand. These are used to take hold of and catch prey. Some even have sharp edges to their ends allowing them to hook into prey for a better grip. On males, one tentacle will be slightly longer than the other. This tentacle is used for sperm delivery and some species will tear off this limb and hand it to the female to be used when needed.
The 8 long arms have suckers running along their entire length. As these are shorter than tentacles they are not for catching prey but mainly for holding the prey towards the mouth after the prey has already been caught. Some species, such as the colossal squid, have hooks running along their tentacles as well for an extra grip.