Mr. W. T. Blanford on Indian Species of Land- Shells. 81 



XI. — On Indian Species of Land-Shells belonging to the Genera 

 Helix, Linn., and Nanina, Gray. By \V. T. Blanford, 

 A.R.S.M., F.G.S. 



In the course of the last few years, much has been published 

 concerning the distribution of Indian and Burmese land-shells, 

 and a large number of novel forms have been described, chiefly 

 by Mr. W. H. Benson. The greater portion of this information, 

 however, has necessarily been derived from an examination of the 

 shells alone, and has left untouched the important question of 

 the forms of the soft parts in the species described. In the case 

 of forms referred to the genus Helix especially, the determina- 

 tion of the presence or absence of a mucous pore at or near the 

 posterior termination of the foot is essential for the natural 

 classification of the different species. I have had opportunities, 

 during the last few years, of collecting several Indian and Bur- 

 mese snails in various parts of the country; and, although my 

 notes on the forms of the animals occupying them are very im- 

 perfect, they may suffice to correct some of the errors which 

 prevail, in conchological works, in attributing various species to 

 the different subgenera of Helix and Nanina*. 



I hope to communicate longer notices of the species enume- 

 rated below at some future time ; for the present I have not the 

 data at hand, and I therefore confine myself to a list of the 

 species actually observed, with the localities from which I have 

 obtained them ; and I have added in italics the names of other 

 species so ck)sely allied to those observed that no doubt can 

 exist as to their subgeneric affinity. With one or two exceptions, 

 which are noted, the observations were made by myself on the 

 living animals. The subgenera in which I have classed the 

 species noted are those of Albers and Pfeiffer, somewhat modi- 

 fied, with a few necessary additions. 



The genus Nanina is naturally divided into two groups of 

 subgenera by the structure of the mucous pore itself; and this 

 subdivision is fully borne out by the characters of the shells 

 belonging to the two groups, although, as is the case more or 

 less throughout the Helicidce, there are some indications of a 

 passage from one group to the other. In the first of these 

 sections the foot is narrow, and more or less abruptly truncated 

 posteriorly ; the mucous pore is situated at the vertical or sub- 

 vertical posterior termination, and has above it a projecting 



* Thus, by Albers, H. Huttoni, Pfr., H. capitium, Bens., and H. Guerini, 

 Pfr., are incorrectly classed under Nanina ; while Nanina Tranquebarica, 

 Fabr., and N. ampulla, Bens., are arranged under Helix. Adams and, I 

 think, Pfeiffer, fall into similar errors, which, indeed, can only be guarded 

 against by an examination of the animals. 



