COCKEEELL : HELIX PIS AN A IN PORTO SANTO. 197 



Balearics, is a similar sort of shell, though, typically depressed. In 

 southern France carpiensis, Let. & Bgh., seems to represent the same 

 kind of thing, but Taylor's figure of a specimen from Coimbra, 

 heavily banded, is probably not true carpiensis. 



True pisana in Porto Santo presents many colour-varieties, 

 usually more or less local. Some have broad red bands on a white 

 ground (var. menJceana, Moq.), others are nearly uniform reddish- 

 yellow (var. concolor, Moq.), some are very delicate and beautiful 

 pink, some nearly black all over, others heavily banded and looking 

 rather like Helix virgata. It would be very interesting to study these 

 forms in detail on the spot, and especially to breed them and 

 determine the hereditary factors. One would expect such a variable 

 snail to eventually split up into a number of species ; and, indeed, 

 many such have been described from Europe and North Africa by 

 Bourguignat and others, but they seem to be imperfectly segregated. 

 Much more field work, with anatomical studies, is required for their 

 elucidation. 



Helix vargasiana, Pfeifier, also described from Porto Santo, is 

 given by Pilsbry as a synonym of hotvditchiana. This cannot be, as 

 it is " perforata conico-globosa, costulata, opaca, cretacea, facsiis 

 nonnuUis obsoletis griseis notata." Apparently it was based on a 

 form of H. pisana. 



