Acetabulum (morphology)

: acetabula) in invertebrate zoology is a saucer-shaped organ of attachment in some annelid worms (like leech) and flatworms.

The name also applies to the suction appendage on the arms of cephalopod molluscs such as squid, octopus, cuttlefish, Nautilus, etc.

It is derived from two Latin words acetum, meaning "vinegar", and -bulum, a suffix denoting "saucer" or "vessel" or "bowl".

[2] In leeches, acetabulum refers to the prominent posterior sucker at the extreme end of the body.

The location and structure of the acetabulum, and the pattern of the spine alignment are important diagnostic tool among trematode species.

Octopus arms contains 200-300 independently controlled suckers that can grasp small objects and produce high adhesion forces on virtually any non-porous surface.