IQO THE DISPERSAL OF SHELLS. 



where a thrush or blackbird had had a meal, and thus it 

 was feared all had vanished. The Vale Castle colonists 

 were seen by Mr. Rimmer during the summer of 1873, 

 but they inhabited only a limited area, and numbered 

 probably not more than a few hundreds. At Vazon 

 Bay, the creatures seem to have done much better, for 

 in the summer of 1876, Mr. Sherriff Tye saw *^ many 

 thousands ^' in that locality, and the following year the 

 colony was reported by the Rev. A. H. Cooke and the 

 Rev. Professor Gwatkin to have extended over an area 

 at least half-a-mile in length, and I find it stated that 

 specimens were again collected in 1884 by Mr. Brockton 

 Tomlin. It is interesting to note, Mr. Cooke and Mr. 

 Gwatkin have pointed out, that the capabilities of these 

 colonies for sustaining life varied directly with the 

 exposed nature of their situation : " that at Sark, on 

 rather high and rocky ground, probably never took 

 root at all, that at Vale Castle, in spite of its north- 

 easterly outlook, was on far more congenial soil, and 

 consequently survived until 1873 o^' later, while that at 

 Vazon, planted on low-lying ground, and facing the 

 north-west; has lived and flourished." ' Mr. Heathcote 

 is said to have planted this snail in considerable numbers 

 in seemingly favourable situations amongst the South- 

 port sandhills, but I do not know with what result ; it 

 is stated also that Mr. T. Rogers has often tried to 



• A. H. Cooke and H. M. Gwatkin, '• Quart. Journ. Conch.," i. 

 pp. 332-3 ; R. Rimmer, " Quart. Journ. Conch.," i. pp. 266-7 ; G. 

 S. Tye, "Quart. Journ. Conch.," i. pp. 230-1 ; J. W. Taylor, 

 " Journ. of Conch.." iv. (1885), p. 275. 



