1922.] B. Prashad : Burmese Unionidae. 105 



collections of Mi. H. F. Blanford" specimens of U. jeddeni obtained 

 from Fedden were labelled as from Burma. Since Fedden had col- 

 lected in both localities the probabilities were that Theobald had 

 mixed up the labels of his specimens. The only specimen of this 

 species now in the Indian Museum collection is from Burma and 

 none of the Central Indian specimens in the collection are referrable 

 to this species It is probable, therefore, that Nevill was correct 

 in considering this species as a true Burmese form. 



Theobald's description of the shell of this species, except for 

 the inaccuracy in his description of the hinge pointed out by me 

 in a recent paper ' , is quite complete and needs no amplification. 



The species is not represented in Fea's Burmese colled ions. 



Parreyssia fcae (Tapparone-Canefri). 



PI. II, figs. 7, 8. 



1889. Uniofeae, Tapparone-Canefri, op. cit., p. 340, 



1900. Parreysiafeae, Simpson, op. cit., p. 814 



1914. Parrtysia feae, Simpson, op. cit.. pp. 1116, 1117. 



1 9 1 5. Parreysia (Parreysia) feae, Preston, op. cil.. p. 16S. 



This species, which was described from specimens collected 

 at Meetan in the Houngdaran River, Burma, has never been 

 figured and was hitherto known only from the author's original 

 description and the short notes added recently by Simpson from 

 an examination of some of Fea's specimens. The following addi- 

 tional notes are based on three specimens one labelled " Type " 

 and the other two " Co-types," which have been presented to the 

 Indian Museum by Dr. R. Gestro of the Genoa Museum. 



The shells of this species vary in outline. In the young they 

 are subrhomboidal but become more elongate as growth proceeds. 

 The zigzag radial sculpture of the young shells becomes obsolete 

 with age and in fully grown shells is just faintly indicated. The 

 umbones are high, recurved forwards and inwards but not meeting 

 in the middle line ; they are often weathered even in half-grown 

 individuals. The young shells are dirty yellow, interspersed with 

 green in the region with raised zigzag sculpture, older shells are 

 yellowish-brown, while the full-grown type is dark chocolate- 

 brown. The nacre is bluish white. 



Genus Lammellidens Simpson. 



1914. Lamellidens, Simpson, op. cit., p. 1 1 65. 

 1919. Lamellidens, Prashad, op. cit., p. 293, fig. 4. 



A large number of specific and varietal names have been 

 given by previous authors to ordinary variations of the commoner 

 Indo-Burmese forms of this genus, and it has been found neces- 

 sary on examination of the large collections of Unionids now 

 available, to drop most of these names. I am now able to recog- 

 nize only six definite species and varieties as occurring within the 



' Prashad, Rtc.Ind. Mus. XIX, p. 713 (1920). 



