 
<translate> Akpa ink bụ ihe dị n'ahụ́ nke a na-ahụ n'ọtụtụ mollusks nke na-eji akpụpụta ink nke na-echebe ha. Ewezuga nke abalị na mmiri miri emi, ihe niile coeloids (squid, octopus na cuttlefish) nke bi na ọnọdụ ọkụ nwere akpa ink, nke enwere ike iji chụpụ igwe ojii nke ink gbara ọchịchịrị iji gbagwojuo ndị na-eri anụ anya.  A na-ejikarị glands ink dị na cephalopods eme ihe maka? Ka anyị buru ụzọ mee ka uche anyị dịrị n'ihe. <eng> An ink sac is an anatomical feature that is found in many cephalopod mollusks used to produce the defensive cephalopod ink. With the exception of nocturnal and very deep water cephalopods, all coeloids (squid, octopus and cuttlefish) which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink in order to confuse predators.

Ink glands in cephalopods are used mainly for? Let's have some stream of consciousness first. 