''Mitromorpha herilda'' is a species of

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk in the family

Mitromorphidae Mitromorphidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Mitromorphidae Casey, 1904. In: MolluscaBase (2018). Accessed through: World Register of Marin ...

Description

The length of the shell attains 7.4 mm, its diameter 3.1 mm. (Original description) The shell is small and white. The

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

consists of at least one

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

, which appears to be smooth. (In our specimens this is somewhat worn.) The five post-nuclear whorls are well rounded and separated by a well impressed suture. They are marked by strong, low, rounded, retractive axial ribs, which are not quite as broad as the spaces that separate them. Of these ribs, about 12 occur upon all the whorls. These ribs disappear shortly after passing over the periphery of the base. In addition to the axial ribs, the surface of the shell is marked by numerous, fine lines of growth. The spiral sculpture consists of well-developed cords, which are about half as wide as the spaces that separate them. Of these cords, 4 occur between the sutures on the first whorl, 5 upon the second, 6 upon the third and 7 upon the penultimate whorl. The base of the shell is marked by about 15 spiral cords, which equal those on the spire in strength and spacing. The aperture is moderately large. The posterior angle is obtuse, scarcely channeled. The outer lip is thin, rendered slightly sinuous by the spiral cords on the outside. The columella and parietal wall are covered with a thin callus. P. Bartsch (1915), Report on the Turton collection of South African marine mollusks, with additional notes on other South African shells contained in the United States National Museum; Bulletin of the United States National Museum v. 91 (1915)

Distribution

This marine species occurs off the

Eastern Cape The Eastern Cape is one of the provinces of South Africa. Its capital is Bhisho, but its two largest cities are East London and Gqeberha. The second largest province in the country (at 168,966 km2) after Northern Cape, it was formed in ...

, South Africa.

References

External links

* {{DEFAULTSORT:Mitromorpha Herilda herilda Gastropods described in 1915