26o THE DISPERSAL OF SHELLS. 



been introduced. But it is, of course, unlikely that this 

 was the case, seeing that the shell is a native of central 

 and southern Europe ; and it seems that its presence 

 can be accounted for in another way, for Dr. Mason 

 ascertained that a quantity of light barley and other 

 seeds (screened out of some samples of barley intended 

 for malting purposes) had been brought into the garden 

 for the purpose of feeding poultry ; and a sample of 

 screenings which he subsequently procured, as already 

 mentioned, contained living shells of Helix caperata} 



BULIMUS DECOLLATUS L., a Mediterranean and now 

 widely distributed species, once found a place in 

 British catalogues^, having been imported, it can hardly 

 be doubted, with plants. Turton, in his " Conchological 

 Notices," of 1826, stated that the creatures had been ob- 

 served to breed in great abundance for many successive 

 years at Watton, in the south of Devon, the seat of H. 

 Studdy, Esq. They were lodged in the earth under the 

 wood-work of a green-house, whence they wandered 

 abroad in summer ; at last, however, when the wood- 

 work and the earth were removed^ the colony was lost, 

 " and all that were preserved we owe to the care of Mrs. 

 Griffiths and Miss Hill." In the "Manual/' in 183 1, 

 Turton added that no foreign earth was ever known to 

 have been admitted into the green-house, and that the 

 animals were considered by the gardeners as natives. 

 Mr. Alder, in 1838, however, remarked that the species 

 could not be regarded as British, and Gray seems to have 



» P. B. Mason, " Journ. of Conch.," iii. (1880-2), p. 118. 



