192 Mr. W. H. Benson on Indian and Burmese 



sulcatis, lateralibus subobliquis, elongatiusculis, rectis, utriusque 

 valvse duplicibus : margarita colore salmonis vix tincta. 



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



Habitat in rivulis et stagnis prope Chunar. 



This species was found by Capt. T. Hutton in tanks and 

 streams near the Fort of Chunar, above Benares, and was noted 

 as Unio No. 19, without name or description, in a paper contained 

 in the fourth volume of the 'Journal of the Asiatic Society of 

 Calcutta/ 



It has two indistinctly raised dark rays on the posterior slope. 

 The gradually compressed form of the hinder edge of the shell 

 contrasts strongly with the inflated form of the central portion. 

 Anterior and posterior cicatrices confluent, apical ones under 

 the cardinal tooth. It belongs to the favidens type of Indian 

 species, and is connected with the more oblique forms by the 

 following species, U. Pinax, which is its representative in the 

 more northerly and westerly tracts of the Gangetic region. 



10. Unio Pinax, B., n. sp. 



JJ. testa transverse oblonga, suboblique ovata, valde insequilaterali, 

 crassa, subinflata, antice rotundata, postice superne sensim de- 

 scendente, demum obtusa, margine ventrali convexiusculo, postice 

 vix emarginato ; disco lseviusculo, concentrice leviter striatulo, 

 antice obsolete radiato-striato, versus marginem ventralem et pos- 

 teriorem plicato ; epidermide olivaceo-fusca ; umbonibus convexis, 

 decorticatis, obsolete radiato-sulcatis, apicibus prominentibus ob- 

 tusis, remotiusculis ; lunula elongato-elliptica ; ligamento brevi ; 

 dentibus cardinalibus crassioribus, radiatim eroso-sulcatis, laterali- 

 bus obliquis, utriusque valvse duplicibus, subflexuosis : margarita 

 albida, iridescente. 



Long. 30, lat. 48, diam. 21 mill. 



Habitat in rivulo Gungun, prope Moradabad, Rohilkhund. 



Anterior cicatrices subconfluent, posterior entirely so, apical 

 ones under the cardinal tooth ; cavity of the beaks very deep. 



11. Unio Leioma, B., n. sp. 



U. testa transverse oblonga, valde insequilaterali, tenuiuscula, tumidi- 

 uscula, antice angustiore, rotundata, postice superne elevatiore 

 convexiuscula, demum subverticaliter truncata, margine ventrali 

 recto ; disco transverse multisulcato ; epidermide cinerascenti- 

 olivacea ; umbonibus convexiusculis, decorticatis, erosis, apicibus 

 remotis ; dentibus cardinalibus brevibus, laminatis, duplicibus, 

 lateralibus rectis breviuscubs, valvse sinistrse solum duplicibus : 

 margarita lactea, vix aurantiaco tincta. 



Long. 23, lat. 50, diam. 17 mill. 



Habitat in regione Dekhan? prope Bombay. 



The subapical tooth of the left valve is lengthened and in- 



