170 UNIONIDJE. 



subventricose, concentrically zoned with bluish green and ochra- 

 ceous yellow, rather glossy, smooth, except at the umbones, which 

 are adorned with longitudinally divergent slender corrugations, 

 the hinder lines of which incline interiorwards, the front ones 

 posteriorvvarcls ; a few similar wrinkles radiate subtransversely 

 thence to the dorsal end of the concave anterior slope ; ventral 

 edge convex ; front dorsal edge straightish, a little elevated ; 

 extremities rounded, the front rather broad ; nacre silvery ; 

 umbonal cavity ample ; teeth laminar, compressed. 



Long. 19, lat. 26-5 mm. 



Hob. Assam. 



The species was originally described from a single valve : below 

 are given the dimensions of two specimens in the British and 

 Indian Museums collections respectively : 



1. 2. 



Long 1(5*75 19 mm. 



Lat 25'5 30 mm. 



Diam 13 1475 mm. 



The above two specimens are the only ones which the compiler 

 of the present volume has been able to examine; though agreeing 

 in the essential characters with the original description, there are 

 still considerable differences between them : the smaller, or British 

 Museum specimen, being far more obtuse posteriorly than that of 

 the Indian Museum, the dorsal margin of the former gradually 

 sloping upwards posteriorly to a rounded angle, while in the latter 

 this character is not nearly so accentuated. 



304. Parreysia (Parreysia) burmanus (Blanford}. 



Parreysia (Parreysia) burmanus (Blanford) ; Simpson, Washington, 

 D.C., Smiths. Inst, Nat. Mus. Proc. xxii, 1900, p. 845. 



Unio burmanus, Blanford, P. Z. S. 1809, pp. 449-450. 



Unto birmanus, H. & T., C. I. 1870, p. 19, pi. 4'2, fig-. 1; Pastel, 

 Conch. Sam. iii, 1890, p. 140. 



Original description: Testa subovata, solida, subcompressa, 

 valde ina3quilateralis, picea vel fusco-olivacea, concentrice plicato- 

 striata, disco medio et postico rugis obliquis irregulariter angulatis, 

 interdum granosis, hie illic praesertim versus marginem veritralem 

 obsoletis corrngato ; umbonibus non prominentibus, subplanulatis, 

 angulatim corrugatis, haud procul ab extremitate anteriore positis; 

 lunella parva, concava; latere antico brevissimo subacuminato- 

 rotundato ; area convexa ; margine dorsali postice regulariter 

 convexo-curvato, terminaliter rotundato, ventrali convexo; den- 

 tibus cardinalibus crassis, radiatim corrugatis, in valva dextra binis, 

 anteriore minimo, in sinistra terriis vel subternis ; lateralibus 

 elongatis subcurvatis, in valva dextra subduplicibus, in sinistru 

 duplicibus ; margarita colore salmonis tincta. Testa junior 



