PUPA. 243 



brother believed that he had once taken P. avenacea (or 

 avena) in Guernsey. It is a local species^ but plentiful 

 wherever it occurs. It is not confined to calcareous di- 

 stricts. Mr. Eyton found it in abundance on the triassic 

 sandstone near Shrewsbury^ where there was no lime- 

 stone (nor, of course, chalk or oolite) within some miles 

 of the place ; and I obsei'ved it in equal plenty on the 

 Molasse in Switzerland. I am also credibly informed 

 that it has been found at Sudbury, near Harrow, on the 

 lower tertiary strata. The variety was found by me at 

 Lulworth in Dorsetshire ; but it is rare. This species is 

 widely diffused throughout Central Europe, ranging 

 south to Corsica ; but it does not appear to inhabit th^ 

 North or extreme South of Europe. 



The young have their shells encrusted with earth or 

 the spores of lichens and mosses, in the same way as 

 Bulimus obscurus; and even adult specimens have occa- 

 sionally a similar covering. From this latter circum- 

 stance I am confirmed in the opinion I ventured to 

 suggest with respect to that species, that the coat is not 

 purposely made by the animal, but is involuntarily caused 

 by the accidental adhesion of extraneous matter to the 

 outer surface of the shell, by means of the slime or 

 a glutinous film which exudes from or invests the epi- 

 dermis. Full-grown specimens have not the same need 

 of disguise for their protection as those which are 

 young and unprovided with teeth. In the daytime the 

 shells are attached by a thin pellicle to the under side of 

 stones and crevices of rocks. 



This is the Turbo juniperi of Montagu ; and the im- 

 mature state is probably the Helix ventricosa of Miiller. 

 There is a great similarity of form between the young 

 of Ptipa and Helix. 



M 



9. 



