JOURNAL OF CONCHOLOGY. 26 1 



Jeffreys' description of burnetii, it is the spire being intorted 

 that distinguishes this remarkable variety. They seem to agree 

 more with Jeffreys' description of the variety lacustris. There 

 is very Uttle difference in the shape of these shells and those I 

 found in Lake Windermere several years ago, the Windermere 

 shells being shorter in the spire. In comparing the burnetti 

 from Loch Skene, and the peregra from St. Mary's Loch, 

 Dumfriesshire, Scotland, Llyn-y-van-fach, Carmarthenshire, 

 Wales, Lake Windermere, Westmorland, and Lake Derwent, 

 Cumberland, I find a great resemblance in the form, and they 

 are all rather strong shells. It was a very good remark of 

 Mr. Nelson that the lesser amount of modification would point 

 to a shorter time of isolation of the Welch shells than those of 

 Loch Skene. 



I think there is a good reason why the shells in these lakes 

 should have this form. There is a great resemblance in the 

 conditions of all these lakes. At the time I visited them there 

 were very few weeds in either of the lakes to protect 

 them, the shells were generally attached to the bare stones, like 

 the Ancylus fiuviatilis ; and although Lake Windermere and 

 Lake Derwent, unlike the other lakes, are protected by trees, 

 they are of such an extent that the wind has great effect upon the 

 waters, and the waves come rolling over the stony beach, and 

 roll the shells about. Now if they had been of the ordinary 

 form and strength of peregra, they must have been broken. 



This I take is an example of the survival of the fittest. 



Helix raffrayl. — I see that M. Bourguignat has described 

 a species under this name from Abyssinia (" Histoire Malac. 

 de I'Abyssinie "), but the name is preoccupied by Tapparone- 

 Canefri for a species from Western New Guinea. I would 

 suggest that the name of the Abyssinian species be changed to 

 Helix raffrayana in order to distinguish it from the New 

 Guinea one. — T. D. A. Cockerell, West Cliff, Colorado, 

 December 8th, 1887. 



