450 MR. W. T. BLANFORD ON OPISTHOSTOMA. [NOV. 2 2, 



tenor half of the curve passes across and completely conceals the 

 umbilicus. 



I have, with some difficulty, detected in O. fairbanki the minute 

 decussating striae observed by my brother between the costulations 

 in O. nilgiricum. They are very difficult to see, even under a high 

 power and strong light, and appear to be frequently obsolete. I 

 cannot detect them in my specimen of O. nilgiricum, which is in 

 good order. 



The bluntly trigonal form of the aperture in O. fairbanki does 

 not appear to be quite constant ; the mouth in some specimens is 

 nearly round. 



The locality at Khandalla, at the top of the well-known Bhore- 

 Ghat incline on the railway between Bombay and Pooua, is some 

 distance down a ravine behind the graveyard, below the hill known 

 as the Duke's Nose. The mollusk lives amongst dead leaves, in the 

 same manner as Diplommatina, but, except in very wet weather, it 

 appears to bury itself in the ground. 



In the paper already referred to, published in the ' Annals and 

 Magazine of Natural History' for June 1864, I gave my reasons for 

 believing in the affinity of Opisthostoma and Clostophis to Diplom- 

 matina, instead of to the Pupinidse, to which Dohrn had referred 

 the first named (in « Malakoz. Blatter,' vol. x. p. 39), and I also 

 showed that the position assigned by Dr. Pfeiffer to Diplommatina 

 in his valuable 'Monograph' was unnatural. In the Second Sup- 

 plement to the • Monograph,' which has since appeared, Dr. Pfeiffer 

 follows my opinion only so far as to assign Cloftophis to the Di- 

 plommatinidse, while he leaves this family with the Aciculidse in 

 the suborder Opisthophthalma, and relegates Opisthostoma together 

 with Arinia to the subfamily Pupinince of the family Cyclophoridse, 

 under the suborder Ectophthalma. To Arinia he, moreover, 

 assigns the two species described by my brother and myself as Di- 

 plommatince, from the hills of Southern India, D. nilyirica and D. 

 kingiana. Had Dr. Pfeiffer seen the two last-named species, he 

 would, I think, scarcely have dissociated them so widely from their 

 nearest relatives the Western Himalayan Diplommatina, one of 

 which, it should be remembered, is the type of the genus. It may 

 be correct to class Arinia with Pupina ; but I cannot help doubting 

 whether the smooth Diplommatinae of South India belong to the 

 same genus as the Philippine Cyclostoma minus of Sowerby, the 

 type of Arinia ; and I am persuaded that the association of Diplom- 

 matina with Acicula and Truncatella is an utter violation of all na- 

 tural affinities. In no single character of shell, animal, or opercu- 

 lum does Diplommatina approach to the Opisthophthalma, so far as 

 I am aware. Its affinities are most unmistakeably with the Ectoph- 

 thalma ; and 1 believe that its proper position is as the type of a 

 subfamily of the Cyclophoridse, which subfamily would include 

 Opisthostoma and the smooth species of Southern India, and proba- 

 bly Clostophis. Whether Arinia should be classed with it or uot, I 

 am not prepared to say. 



