Page:VCH Sussex 1.djvu/154

 MOLLUSCS The soil and climate of Sussex, as well as its diversified physical features, are favourable to moUuscan life. The chalky south downs swarm with some species, which it is even claimed are the cause of the excellent flavour of the mutton grown in that district ; the woody copses and remnants of the Wealden forest shelter others ; while, though there are no very large rivers, the numerous streams, especially of the Pevensey Level, yield a great number of aquatic forms. Out of the 139 species known to inhabit the British Islands, no less than 105 have been recorded as occurring in the county. Among these we have not reckoned the Roman snail {Helix pomatid) because the sole evidence of its presence depends on a single dead shell found in the Lady Holt covers near Harting, and though an attempt was subsequently made to establish a colony there it did not succeed. Why this species, so abundant on the north downs, should be absent from such an apparently equally favourable situation as the south downs is a mystery. A few other absentees, such as Vitrea glabra, some of the Vertigos and of the slugs, may yet be discovered. The assemblage is of the average British type with the addition of two forms of interest, viz., Helicella cartusiana and the cheese snail {Helicodonta obvoluta), which last local species has been traced by Mr. Clement Reid, F.R.S., along the northern escarpment of the south downs, in ancient beech woods, from Harting to the river Arun, with a few colonies in the middle of the downs towards West Dean and Singleton. The literature of the subject is very scattered, but the more important papers are those by Mr. J. E. Harting' and Mr. J. H. A. Jenner,^ the latter which deals with East Sussex including the work of all previous writers. A. GASTROPODA I. PULMONATA Agrwlimax agn-stis (Linn.) _ /a^is (Mull.) a. StYLOMMATOPHORA. ,■ ^ ;-/ir( Amalia iowerbti [r er.) Testacella scutu/um, Sby. Lewes. (Specimens — gcgi'ta (Drap.) Hastings from Newport, Isle of Wight, have Vitrina pcllucida [MuW.) been turned loose at Chichester) Fitrea crptallina (Mull.) Limax maxirnus, Linn. — alliaria (Miller) — flavus, Linn. — cellarui (Mull.) — arborum, Bouch. -Chant. West Sussex — nitidula (Drap.) 1 Zoologist, 1878, pp. 84, 122, 161. (1891) p. 361, to which <T few more species have been added by Mr. W. Whitwell, ibid. vol. x. (1901) p. 86. 108
 * Trans. Eastbourne Nat. Hist. Soe. vol. viii. (1884) p. 44 ; and supplement Jourv. Conch, vol. vi.