1922. J B. Prashad : Burmese Unionidae. 101 



are ever developed ; in P. mandclaycnsis on the other hand the 

 tubeicles are always distinctly developed and the sculpture is 

 much coarser, and (iv) the hinge of P. bhamoensis has lamellar 

 pseudocardinals winch are not very thick, not at like tooth-like 

 and only slightly ragged. 



In the Indian Museum collection the species is represented 

 by the type-specimen from Bhamo and a fair series of specimens 

 of all ages from Sagaing, Zayleyman and Tavoy in Burma. 



Parreyssia mandelayensis (Theobald). 



1873. Unio mandelayensis, Theobald, op. cit., p. 208, pi. xvii, fig. 2. 

 1876. Unio m and el ay anus. Hanley and Theobald, op. cit., p. 62, pi. 



cliv. fig-. 4. 

 1878. Unio bhamoensis (in part), Ncvill, op. cit., p. 900. 



1889. Unio mandelayensis, Tapparone-Canefri, op. cit., p. 342. 



1890. Unio mandelayensis, Paetel, op cit.. p. 158. 



1899. Unio mandelayensis, von Marions, op. cit., p. 38. 



1900. Parreysia bhamoensis (in part), Simpson, op. cit , p. 843. 

 1914. Parreysia mandelayensis, Simpson, op. cit., pp. 1112, 1113. 



1 c 15. Parreysia {Parreysia) bhamoensis (in part), Preston, op. cit., pp. 

 163, 164. 



The question of the validity of this species as distinct from 

 P. bhamoensis has been discussed already in the account of the 

 latter species, and I would only note here the distinguishing 

 features of the species. 



The shell is triangular with a very high and forwardly placed 

 beak, the beak and the umbonal region are both very strongly 

 sculptured and often have distinct tubercles or even spines 

 developed in this region. The hinge is very strong, with compact, 

 thick and distinctly tooth-like pseudocardinals. 



I have examined a specimen from Theobald's collection, 

 which is the one figured by him in the paper cited above and is 

 probably the type of the species. Besides I have examined one 

 of the specimens named by Tapparone-Canefri, and other speci- 

 mens in the Indian Museum collection from Bhamo, Sheinmagah, 

 Maydong and Pegu in Burma. 



Parreyssia houngdaranicus (Tapparone-Canefri). 

 PI. II, fig. 6. 



1889. Unio houngdaranicus, Tapparone-Canefri, op. cit., p. 341. 

 1900. Parreysia tavoyensis var. triembolus [in part), Simpson, op. cit., 

 p. 844. 



1914. Parreysia tavoyensis var. triembolus (in part), Simpson, op. cit., 



pp. 1 1 15, 1 1 16. 



1915. Parreysia tavoyensis var. triembolus (in part), Preston, op. cit., 



p. 167. 



Simpson, on the basis of a specimen labelled U. houngdarani- 

 cus from Fea's collection in the U.S. National Museum, placed 

 U. houngdaranicus in the synonymy of what he called Parreysia 

 tavoyensis var. triembolus, but from his remarks it appears that 

 he was not quite certain as to the correctness of his conclusions. 



