DISPERSAL BY MAN. 247 



observed, is by no means confined to the sea-board, 

 and in his opinion the fact of its range in this country 

 being Hmited to a few places on the coast is suggestive 

 of the idea that it may have been originally " brought 

 over in ballast from the Continent, or perhaps from 

 Jersey." ^ 



Helix obvoluta Mull. This species (the cheese 

 snail of Gray's " Turton "), unknown as an inhabitant of 

 this country to the early writers on our conchology, 

 was first recorded as British in March, 1831, by Dr. 

 James Lindsay, who discovered it, in 1830, "apparently 

 indigenous," amongst moss -near the roots of trees in 

 Ditcham Wood, near Buriton, Hampshire, and it was 

 to be found, he added^, for a considerable distance along 

 the chalk escarpment of the South Downs facing to the 

 north. He had collected more than twenty specimens.^ 

 The creature inhabits central Europe, and occurs, also, 

 according to the " British Conchology," in the north of 

 France ; its indigenousness in Britain was doubted by 

 Mr. Jeffreys (1831), who observed that "its confined 

 locality and the circumstance of its having remained so 

 long unnoticed by British authors might warrant a 

 suspicion that it may be of the same recent and pre- 

 carious indigenousness in this country with the //. 

 carthusianella^^ {ov cartusiana) which he then regarded 

 as a possible importation from France."^ Gray (1840) 



' "Jeffreys," i. (1862), pp. 208-9; "' Rimmer," (1880), p. 133, 

 "^ J. Lindsay, "Trans. Lin. Soc," xvi. (1833), p. 765. 

 ^ J. G. Jeffreys, in the supplement to his "Synopsis" read m 

 1831, "Trans. Lin. Soc." xvi. (1833), p. 510. 



