A Field Guide to the Snails of Lord Howe Island

154 pupiform - with a pupa-shaped shell. sculpture - a raised or incised pattern on the surface of a shell, often consisting of some combination of radial and spiral elements. sinistral - shell coiled in a left-handed or anti-clockwise direction. semislug - a snail with a reduced, ear-shaped shell that it cannot fully contract its body into. This is an intermediate step between a snail and a slug. slug - a snail with a fully absent or internalised shell. species - a taxonomic category defining a group of living organisms that are able to interbreed and produce viable offspring with one another. spire - the apex of a shell, consisting of all whorls but the last one. subspecies - a taxonomic category below the level of species. Subspecies often reflect geographic groups that have some degree of distinctiveness but may be able to interbreed with one another. sulcate - a shell with a sulcus, which is a groove or furrow that is found on each whorl. supraperipheral sulcus - a sulcus (groove or furrow) that is situated just above the whorl periphery. sutures - the lines along which adjoining whorls meet. synonyms - two or more scientific names that refer to the same species or genus. The earliest name is referred to as the senior synonym and is considered to be the correct name. Any later names are junior synonyms. taxonomy - the science of naming, describing and classifying living organisms. trochoidal - with a shell that has a conical spire and a flat base. turbinate - with a top-shaped shell. umbilicus - a depression in the lower surface of a snail’s shell, where the underside of the spire can be seen. Varies in width between species and is completely closed in some species. viviparous - a species that gives birth to live young. whorl profile - the shape of the periphery of the shell, best viewed from the side. whorls - coils of a snail shell.