1922.] B. Prashad : Burmese Unionidae. 97 



added by me ■ later. I have nothing further to add regarding 

 these two species (P. micropteroides Annandale and P. ferrugineus 

 Annandale). 



Genus Pseudodon Gould. 



1844. Pseudodon, Gould, Proc. Boston Soc. Nat. Hist. I, p. 161. 

 1853. Monodontina, Conrad, Proc. Acad. Nat. Sci. Philadelphia, VI, p. 

 269. 



1914. Pseudodon (in part), Simpson, op. cit.. p. 1079. 



1915. Pseudodon s. s. (in pari), Preston, op. cit., p. 152. 



1919. Monodontina, Prashad, Pec. hid. Mus. XVI, pp. 403-408. 



1920. Pseudodon (subgen. Monodontina), Haas, op cit., p. 318. 



I am afraid I am responsible for introducing some confusion in 

 the already confused state of affairs regarding this genus. In the 

 paper cited above I revived the generic name Monodontina for 

 species like P. vondembuschiana , since the animal of P. chaperi, 

 which I consider as one of the varieties of this species, was very 

 different from that of P. sahvenianus (wrongly spelt salvenianus) 

 described by me in a previous paper. 1 in the genus Monodontina I 

 also included the species P. inoscularis as a variety of P. vondembus- 

 chianus, having through oversight considered P. salwenianus, in- 

 stead of P. inoscnlaris, as the type of the genus Pseudodon. Since 

 the genus Monodontina, with P. vondembuschiana as its type-species, 

 is synonymous with Pseudodon with P. inoscnlaris as its type, the 

 former name must give way to the latter, it having been described 

 about nine years after Pseudodon. The genus Pseudodon as now 

 restricted will include the sp3cies or varieties orbicularis , cambod- 

 jensis, oralis, ellipticus, zollingeri, vondembuschianus, chaperi, 

 ponderosus and inoscnlaris. The specimen which I doubtfully 

 assigned to cumingii (loc. cit., p. 408) is not the true cwningii 

 and cannot be included here. 



Pseudodon vondembuschiana var. inoscularis (Gould). 



1919. Monodontina vondembuschiana var. inoscnlaris, Prashad, op. 

 cit., p. 408. 



1921. Pseudodon (Pseudodon) inoscularis, Haas, op. cit., p. 341, pi. 



xlii, fig. 7. 



In the paper cited above I have given reasons for considering 

 this species as a variety of Lea's vondembuschiana , but as I have 

 stated above I made a mistake in adopting the generic name 

 Monodontina. 



In the Indian Museum collection this variety is represented 

 by two specimens from Tenasserim. 



Genus Trigonodon Conrad. 



1865. Trigoncdon, Conrad, Amtr. Jonrn. Conch. I, p. 233 



In view of the differences in hinge and other shell characters of 

 the species that now have to be assigned to the genus Pseudodon, 



« Prashad, Pec. Hid. Mus. XIV, pp. 183-185, pi. xxii (1918) and XVI, p. 

 294, fig. 5 (1919). 2 Prashad, Pec. Ind. Mus XVI, p. 295, fig. 6 (1919). 



