Coriocella is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of small slug-like sea snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod molluscs in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Velutinidae

Velutinidae

Velutinidae is a family of small sea snails, marine gastropod molluscs in the clade Littorinimorpha.- Taxonomy :The following two subfamilies have been recognized in the taxonomy of Bouchet & Rocroi :* subfamily Velutininae J. E...

.

Description

The ear-shaped shell is extremely thin, even membranous in part and concealed in the mantle

Mantle (mollusc)

The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

. It has a small spiral turn at the apex

Apex (mollusc)

Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...

. The aperture

Aperture (mollusc)

The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

 is very large. The shell lacks a columella.

The soft body is elliptical and much depressed. The borders of the mantle are very thin, notched in front and spreading out widely. The oval foot is very small. The head is scarcely distinct. The two short and rather thick tentacle

Tentacle

A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...

s are contractile and concealed under the shield. The eyes are situated at the base of the tentacles.

Species

Species within the genus Coriocella include:

• Coriocella fella Er. Marcus & Ev. Marcus, 1970
• Coriocella hibaye Wellens, 1991
• Coriocella jayi Wellens, 1995
• Coriocella nigra Blainville, 1824
• Coriocella safagae
  Coriocella safagae
  Coriocella safagae is a species of small sea snail with a transparent internal shell, a marine gastropod mollusk in the family Velutinidae. Because the shell is mostly internal, the snail resembles a sea slug in general appearance....
  
  Wellens, 1999
• Coriocella tongana (Quoy & Gaimard, 1832)