DISPERSAL RY MAN. 259 



lake. Miss Warren suggests that it may have been 

 a collection-escape. No one residing in the neigh- 

 bourhood, however, is known to possess West Indian 

 shells, but, by one means or another, quite possibly, the 

 specimen may have been carried, perhaps by a stream, 

 from a considerable distance. 



BULIMUS UNDATUS Brug. Sir C. Lyell, in the 

 '' Principles,^' stated that B. undatus, a West Indian 

 shell of considerable size, had been imported, adhering 

 to tropical timber, into Liverpool, and, as mentioned in 

 the last chapter^ he was informed by Mr. Broderip that 

 the creature had become "naturalized in the woods 

 near that town." It can hardly be assumed, I think, 

 that the animal is, or ever was, really acclimatized here ; 

 Gray, however, in 1840, and again in 1857, speaking of 

 it as B. zebra, mentioned its importation with mahogany 

 logs, and remarked that it often lived for some time in 

 this country. I am not aware that specimens have 

 been found during recent years. ^ 



BULIMUS DETRITUS Miill. In 1880 or 1881, Dr. P. 

 B. Mason wrote to the "Journal of Conchology^' that 

 more than a dozen specimens of B. detritus^ in various 

 stages of growth, most of which were alive when found, 

 had recently been brought to him as having been taken 

 from a rockery in a garden in the neighbourhood of 

 Burton-on-Trent. They occurred among a number of 

 dead littoral shells, gathered at Scarborough, with 

 which the owner of the garden was certain they had 



^ "Principles," ii. p. 371 ; Gray's " Turton," 1840, p. 7 ; 1857, 



p. 292, V 



S 2 



