Onchidiopsis corys is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small sea snail

Sea snail

Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

 with a transparent internal shell, a 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 mollusk 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...

. Because the shell is mostly internal, the snail resembles a sea slug in general appearance.

Distribution

This marine species can be found along the coast of Newfoundland and Labrador

Newfoundland and Labrador

Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

.

Description

The broadly ovoid snail has a maximum recorded length of 20 mm. It is cream-colored with about eight brown spots. The thin dorsal surface (notaeum) is smooth on top and on the sides, but wrinkled and vesiculate elsewhere. It envelops the transparent, thin, white internal shell. The shell shows some faint concentric lines of growth. This shell covers the top and the sides of a large visceral hump, suggesting in its form a Homeric helmet (Greek : korys), hence the name of the epithet corys. This hump is a smooth dome of purplish-yellow visceral mass, mainly consisting of the glands of the genital system.

The osphradium

Osphradium

The osphradium is the olfactory organ in certain molluscs, linked with the respiration organ.The main function of this is to test incoming water for silt and other possible food particles.It is used by all members of the Genus Conus....

 is black at its base and has a peculiar form. The gill leaflets are not auriculate.

The foot shows a large proboscis

Proboscis

A proboscis is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In simpler terms, a proboscis is the straw-like mouth found in several varieties of species.-Etymology:...

 with a truncated-cone shape. On the foot are also two tentacles, about the same length of the proboscis, with conspicuous black eye spots. The large penis is situated on the right side of the neck above the right tentacle.

The taenioglossan radula

Radula

The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

has the usual formula with seven teeth in a row : 2 + 1 + 1 + 1 + 2. The central tooth is arched and is at its base about as wide as high. Its top forms a dentate, cusplike blade. The lateral teeth are higher and somewhat narrower at their base. The marginal teeth are formed like arched claws, curving upward, backward and slightly outward. The inner uncinal hooks are nondenticulate.

All these characteristics sharply differentiate Onchidiopsis corys from the other species in this genus.