UXIO. XOBULAUrA. 135 



pseudocardiuals compressed ; beak cavities well excavated, not 

 compressed. Animal highly coloured, anal opening crenulate or 

 smooth." 



265. Unio mongolicus, Mkldemhrff. 



Unio moiJffolicKs, MiddendoriT, Sib. Ifeise, ii, 1851, p. 277, pi. 27, 

 figs. 7, 8; Ilessling, Perl, uiid Hire Perlen, 1859, p. 203; 

 Schrenck, Ileise und Forsch. im Anuir-Laiide, ii, 1867, p. 699: 

 Westerlund, Kong. Sveusk. Vet.-Ak. Haiidl. xiv, no. 12, 1876, 

 p. 74; Poetel,"Conch. Sam. iii, 1890, j). 159 ; W'esterliind, Faun, der 

 Pal. ii, pt. 7, 1890, p. 113. 



Original descriiition: — Testa transversim oblonga, subreniformi, 

 tumescente, fusca ; latere postico anticum quater superante ; mar- 

 gine ventrali nonniliil retuso ; niargine cardinali primo ventral! 

 parallel! et timi, inde a dimidio latitudinis, in rostrum asymmetri- 

 cuin, inferum, desceiidente ; umbonibus proininulis, erosis ; den- 

 tibus cardiualibus parvis, crassiusculis ; dentibus lateralibus 

 evolutis. 



Long. .'32, hit. 76, diam. 24 mm. 



Hah. A mountain stream at Gorbitza in Daurien. 



There is a single specimen in the National Collection which 

 is indistinguishable from that in the Indian Museum from the 

 Upper Indus. 



Genus NODULARIA. 



Nodularia, Conrad, Proc. Acad. Nat. Sci., Pliiladelplua, vi, 1853, 

 p. 268 ; Sim])son, AVashington, D.C, Smiths. Inst., Nat. Mus. 

 Proc. xxii, 1900, p. 806. 



Type, Unio dongJasia', Gray ; China. 



Range. China; Japan; Eastern Siberia; Indo-Chiua; India; 

 Borneo ; Java ; Sumatra : New Guinea ; Africa. 



Shell nodose; cardinal teeth robust, single in the right valve; 

 in each valve the principal cardinal tooth is parallel with the 

 lateral teeth, or directed towards the posterior extremity of the 

 shell. 



Section JS'ODULARIA (sensu siricto). 

 See above. 



266. Nodularia (Nodularia) digitiformis (Sowerhg). 



Nodularia {Nodularia) difjitiformis (Sowerbv) ; Simpson, Washing- 

 ton, B.C., Smiths. Inst., Nat. Mus. Proc.,'xxii, 1900, p. 809. 



Unio digitiformis, Sowerbv, Conch. Icv.i. xvi, 1868, pi, 65, 

 tig. 333 ; IVtf'l. Conrli. Snni. iii. 1890. p. 1-50. 



