Cepaea nemoralis

The grove snail, brown-lipped snail or lemon snail (Cepaea nemoralis) is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc. It is one of the commonest large species of land snail in Europe, and has been introduced to North America. Subspecies Cepaea nemoralis etrusca (Rossmässler, 1835) Cepaea nemoralis nemoralis (Linnaeus, 1758) Cepaea nemoralis is the type species of the genus Cepaea. It is used as a model organism in ecological genetics, including in citizen science projects. Cepaea nemoralis is among the largest and, because of its bright colouration, one of the best-known snails in Western Europe. The colour of the shell is highly variable; it ranges from brown, through pink, to yellow or even whitish, with or without one to five dark-brown bands. Names for many colour variants were coined in the nineteenth century but this system has been replaced by an independent scoring of shell colour and the presence/absence and fusion of individual bands numbered 1 to 5. The thickened and slightly out-turned apertural lip of adults is usually dark brown, but can be white in some regions. The umbilicus is closed in adults but narrowly open in juveniles. The shell surface is semi-glossy. An adult shell consists of 41⁄2–51⁄2 whorls, with a width of 18–25 mm and a height of 12–22 mm. Cepaea nemoralis is closely related to Cepaea hortensis. They share much the same habitat and exhibit a similar range of shell colours and banding patterns. Cepaea nemoralis tends to grow larger, but usually the species can most easily be recognised by the colour of the lip of adult shells. In a high proportion of regions, C. nemoralis consistently has a dark-brown lip to its shell, whilst C. hortensis has a white lip. In areas where lip colour is variable, dissection is necessary. A cross-section of the love dart of C. nemoralis shows a cross with simple blades, whereas that of C. hortensis has bifurcated blades. The mucus gland has 3 or fewer branches in C. nemoralis, but 4 or more in C. hortensis.