156 UJTIOXID.I. 



versus eminentes subradiata ; margine dorsali vix declivi, antice 

 concavo ; margine ventrali coiiA'exo ; lunula distincta niargarita 

 albida, dentibus cavdinalibus validis, laciniatis, baud laminatis. 



Shell small, green, subventricose (but varying in sliape from 

 elliptic to rounded oval), scarcely inequilateral, smooth, except 

 near the prominent beaks, which are adorned with somewhat 

 radiating, oblique, linear ridges ; dorsal edges not much sloping, 

 the front one concave ; ventral margin convex ; luuule well 

 mai'ked, nacre nearly white, cardinal teeth strong, jagged, not 

 lamellar. 



No dimensions being given in either of the above descriptions 

 the following are taken from three specimens in the Indian 

 Museum collection ; jS^o. 1 being a specimen from the River 

 Dnkaree, and Nos. 2 & 3 from Ceylon : — 



1. 2. 3. 



Long 32-5 24-5 20-75 mm. 



Lat 42-75 3G 28 mm. 



Uiam 19-25 175 14-25 mm. 



A-ar. fragilis, Jl. 4' T., C. 1. p. 21, pi. 45, fig. 4. 



Presumably a thin form. 

 Long. 29, lat. 41 mm. 



Var. laevirostris [Benson) ; Simpson, Washington, D.C., Smiths, 

 Inst., Nat. Mus. Proc. xxii, 1900, p. 842. 



Vnio lavirostris. Benson, A. M. N. II. x, 1862, pp. 191--192 ; 



Blanford, J. A.'S.B. Calcutta, xxxv, 1862, p. 144. 

 Unio cornif/atus, var. Icevirostris, II. & T., C. I. 1876, p. 21, pi. 44, 



tigs. 0~ij. 



On(jinal description : — Testa transverse oblonga, subovata, valde 

 inajquilaterali, crassiuscula, uiedio subtumida, autice superne 

 breviter angulata, deinde roLundata, postice superne sensim 

 couvexe descendente ; demum rotundata, margine ventrali con- 

 vexiusculo ; disco la)viusculo, concentrice leviter striato ; epi- 

 dei'mide olivaceo-viridi, fusco fasciata; umbonibus convexis, 

 decorticatis, obsolete radiato-sulcatis, apicibus promiuentibus, 

 aippi'oximatis ; lunula impi-essa, elliptica ; ligamento elongato ; 

 dentibus cardiualibus brevibus, crassiusculis, eroso-sulcatis, later- 

 alibus subobliquis, elongatiuscidis, rectis, utriusque valvie duplic- 

 ibus ; margarita colore galmonis vix tiucta. 



Long. 28, lat. 50, diam. 20 mm. 



Bab. Streams and ponds near Chuuar above Benares : repre- 

 sented in the Indian Museum collection by localized specimens 

 from the Chittagong Hills, Sudiya and Arrah. 



Benson's description is supplemented by a short note from 

 which the following quotation is taken : — " It has tA\-o indistinctly- 

 raised dark rays on the posterior slope. The gradually compressed 



