241 



NOTES ON ARIOPIIANTA, XESTINA, NILGIRIA, AND EUPLECTA, 

 WITH LISTS OF SPECIES. 



By W". T. Blanford, LL.D., F.B.S., etc. 



Read Uth Jane, 1901. 

 PLATE XXV. 



We are indebted to Colonel Godwin - Austen for the remarkable 

 discovery that in certain areas of the Indo-Malay (Indian or Oriental) 

 region, members of tbe Limacidae (Zonitida)), having shells so diverse 

 that tbey were formerly classed in distinct genera, or even in some 

 cases in different families or subfamilies, agree amongst themselves in 

 each area, and differ from tbose in other areas by characteristic 

 details in the anatomy, details which, in the presence of the extra- 

 ordinary similarity which prevails throughout the greater portion of 

 the terrestrial Pulnionata, are sufficient to distinguish each local 

 group. Tbis discovery has entirely upset all previous attempts at 

 the classification of the Indo-Malay Limacidoe, and at present we can 

 only arrange the species known in provisional local generic sections. 



A considerable proportion of the larger forms of Limacida3 in 

 Peninsular India and Ceylon formerly referred to Malayan and 

 Philippine genera, like Hemiplecta and Xesta, have now been shown to 

 belong to one or another of the genera or subgenera cited in the title 

 of this paper. In consequence of Godwin-Austen's recent work, some 

 of the results of which, not yet published, he has communicated to me, 

 it is now practicable to arrange generically many of the species known 

 to occur in the zoological sub-region consisting of India south of the 

 Himalayas and Ceylon, the area which I have proposed to call the 

 Cisgangetic sub-region. It is true that the animals of several species, 

 in addition to those already dissected, require examination before their 

 affinities can be correctly ascertained, but still an attempt can now be 

 made at classification. Amongst the species that still require 

 examination are Helix Basileus, Bs. (the shell of which closely 

 resembles that of certain Siamese forms of Hemiplecta), H. Basilessa, 

 Bs., H. concavosptra, Pfr., and H. apicata, Blf. 



In drawing up lists of the species it must be understood that 

 I accept Godwin-Austen's view (Land Freshw. Moll. Ind., vol. i, 

 p. 133; vol. ii, p. 82) that Ariophanta should be restricted to Indian 

 (Cisgangetic) species; also that his subgenus Nilgiria (op. cit., vol. ii, 

 pp. 77, 81, 123) is distinguished from Ariophanta solely by having 

 dextral instead of sinistral shells, a character which I agree with him 

 in regarding as of no real importance, and that for the present, at all 

 events, the genus Ewplecta (op. cit., vol. ii, p. 96) should be confined 



