250 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



two very diBtinct and separate portions. There are some minor 

 differences in the radulfe of the different species, but on the whole 

 they appear to me nearer to Macrochlamijs than to any other genus. 



Oxytes ranges from Darjiling (0. orobia), the Bhutan Hills, and the 

 Khasi Hills, to Burma and Tenasserim. 



Be7isonia is represented in the ISTorth-West Himalaya by B. lahiata, 

 and thence ranges to Kashmir and Murree, and in B. Wynnei to the 

 arid Kuttak Hills, near Peshawur, and the Kuram Yalley. Tt is 

 thus a North-West Indian genus. I am, however, inclined to think 

 a species like, or near to B. convexa occurs at Darjiling, but I have not 

 met with any animal that could be referred to it in the Eastern Hills 

 or in Southern India. 



Passing south-eastward towards the confines of the area I have 

 defined for Macrochlamijs, we find a change commencing in M. re- 

 splendens (section E), of Tenasserim; we have the shell-lobes still 

 present, but the generative organs are modified in that the coiled 

 mass has gone, and the male organ is more like that of Hemiplecta 

 {Humphrey siana). In a large Siamese species we find the same 

 features, and I think we are here beyond the range of the Indian 

 type of the genus. 



I have failed to find among any Macrochlamys-like shells of 

 Peninsular India the exact similarity of anatomical detail so typical 

 of the genus ; there are many shells in this part of India which up to 

 the present are included in it, among them being M. pedina and 

 M. platychlamys, from Bombay. The first-named I include in section 

 D of Macrochlamys. It has both the right and left shell lobes, but the 

 fonner is extremely rudimentary, and judging from analogy and its 

 reduced size in spirit, it cannot be largely protrusible in life. The male 

 organ has become altered in form, its most interesting feature being 

 the replacement of the many-coiled disc by a simple short bend in a 

 coecum-like process, the retractor muscle rising beyond and above this. 



The other species, platychlamys, presents far greater diversity when 

 compared with species of Macrochlamys. The broad shell-lobes cover 

 the shell almost completely in life, and the generative organs are on 

 a very different plan, and comparatively simple in detail. The exami- 

 nation of the Ceylon shell regulata presented anatomical characters 

 of the same type, and I have therefore placed these two species in 

 a new subgenus, Eurychlamys {see Appendix). The most interesting fact 

 in connection with this particular development is the discovery that 

 a Sikkim and Bhutan species, planospira, must be included with them. 

 I previously placed planospira, on account of its shell-lobes and 

 shell (besides not taking into sufficient consideration all the details 

 of its internal anatomy), in Austem'a, but it will be seen that its 

 anatomy does not at all resemble that of the latter genus. 



Continuing the review of the shells of Peninsular India and Ceylon, 

 I have been fortunate in obtaining through various friends, among 

 whom I may mention Dr. Thurston, Mr. Phipson, Mr. W. T. Blanford, 

 and particularly Mr. Collett in Ceylon, other species preserved in 

 spirit, and I am enabled to point out a few details of their general 

 anatomy. They represent six genera, viz., Ariophaiita, Nilgiria, 



