Maximum size: 5 -7 cm This one is a juvenile, approx. 0.8 - 1 cm

Depth: 1 - 17 m

Family of exclusively marine snails that occur almost worldwide in warm,

temperate and cold seas.

They live together with sea squirts, which they mainly feed on

and lay their egg capsules in their empty shells.

Coriocella nigra belongs to the Velutinidae family.

At first glance, these snails look like nudibranchs,

but have a complete inner shell, which is covered by the mantle.

Thin shell, heavily to moderately calcified with an ear-shaped, low spire

with widened opening, smooth or weakly shaped by axial growth lines,

completely enclosed by the mantle.

Periostracum thin.

Coriocella can be easily recognized by its external morphology

by the presence of a variable, species-specific number of humps,

which are clearly visible on the back of living animals

and the typical light brown or dark velvety coloration.

There are two very different color patterns in Coriocella nigra:

A black one, velvety in appearance, dark blue or dark green veined

and a light brown variant with dark brown veins.

It lives under reef overhangs and in caves.

The turtleback, as Coriocella nigra is colloquially known,

imitates the appearance of a sponge.

Bangka island North Sulawesi