414 Mr. W, H. Benson on a singular Shell from South India, 



Finally, the appearance produced by these readily moveable 

 and extraordinarily flexible parts in the protean system of 

 filaments, as if a moving fluid substance assumed any form, or 

 spread and poured itself into any shape, is an illusion which is 

 set up especially by the circumstance that individual minute 

 parts which are readily displaceable throughout can never be 

 distinguished at their points of contact. 



XLIII. — Description of a singular Shell from Southern India, 

 allied to Tanalia ; with Remarks on a Travancore Batissa, and 

 on the Himalayan Form Tricula. By W. H. Benson, Esq. 



Tanaliai^.) Stomatodon, Bens., n. sp. 



T. testa ovato-globosa, solida, Iseviuscula (juniorum polita), striis 

 spiralibus obsoletis induta, olivaceo-nigrescente ; spira brevi erosa, 

 sutura impressa ; anfractibus 3 superstitibus, superioribus con- 

 vexiusculis, ultimo convexo ; apertura ovato-acuta, albida, intus 

 demum angustiore, sinuata ; peristomate integro, margine dextro 

 basalique acuto, columellari late calloso, infra latiore, subito intus 

 truncate, dente prominente crasso munito. 



Axis 14, lat. 12 mill. 



Habitat in aquis dulcibus montium prope Cottyam, regionis Travan- 

 corise. Invenit D. Kohlhoff. 



This very interesting shell was sent to me by Capt. Charles 

 Annesley Benson, at whose request the discoverer 

 had kindly searched the Travancore Hills behind 

 Trevandrum for land and freshwater shells. Among 

 the former was a specimen of Helia: Basileus, Bens., 

 larger than the type-specimen described in the TanaiiTc?) 

 Annals of Natural History for February 1861. stomatodon. 



The form now made known is a very distinct species of the 

 Paludomoid type ; and should it prove to be a Tanalia, as sur- 

 mised by Mr. H. F. Blanford, who has carefully studied the 

 family, it will stand as the first of the genus which has occurred 

 out of Ceylon. Unfortunately, all the specimens were deficient 

 in the operculum, which, when examined, may possibly authorize 

 its transfer to a new genus, in which case the specific name may 

 fairly be employed to designate it. In my remarks on Clea 

 Annesleyi, from Quilon, in the Ann. Nat. Hist, for October 

 1860, I observed that, notwithstanding the basal emargination, 

 Clea, with reference to its unguiculate operculum, would proba- 

 bly be found to have nearer relations with the Cingalese genus 

 Tanalia than with Melania and its congeners. Stomatodon seems 

 partly to supply one of the absent links, inasmuch as its oper- 

 culum must necessarily be provided with a basal projection, 



