1098 PSFCUDODON 



Monocondylcca mouhotiana Lea, Jl. Ac. N. Sci. Phila., VI, 

 1866, p. 65, pi. XXI, fig. 62 ; Obs., XI, 1867, p. 69, pi. XXI, 

 fig. 62. — Clkssin, Conch. Cab. Ano., 1876, p. 261, pi. lxxxii, 

 figs. I, 2. 



Mar^aron ( Mo)iocondyla\i) iiionliotiana LEu\, Syn., 1870, p. 



73- 

 Unio rnouJiotianus Sowcrby, Conch. Icon., XVI, 1868, pi. xcii, 



fig- 503- 

 Pseudodon nionhotianus Morelet, Ser. Conch., IV, 1875, p. 



339- 

 Pseudodon moithoti Simpson, Syn., 1900, p. 839. 



Elongated, rather thin and subcompressed. It does not 

 seem to be as much inflated as P. exilis. 



PsEULX)DON Exii.TS (Morelct). 



Shell elongate, subrhomboid, inequilateral, thin, convex or 

 subinflated ; beaks not prominent ; anterior end narrowed and 

 rounded ; dorsal outline lightly curved ; dorsal slope obliquely 

 tuncated ; base line almost straight, full behind the middle ; 

 posterior ridge widely rounded ; posterior end rounded below ; 

 surface with strong growth lines ; epidermis tawny-brown ; 

 teeth single in each valve, small, compressed ; nacre bluish, ful- 

 vous in the cavities. 



Length 57, height 30, diam. 18 mm. 



Perak. 

 Monocondylus exilis Morei.ET, Jl. de Conch., XIV, 1866, p. 63. 

 Pseudodon exilis Morelet, Ser. Conch., IV, 1875, p. 340, pi. 



XVII, fig. I. — Simpson, Syn., 1900, p. 839. 



I suspect that this is merely a variety of P. mouhoti. The 

 beaks are not quite so. near the anterior end as they are in 

 that species, the shell is more tawny, more strongly, obliquely 

 truncate on the dorsal slope, and more inflated. 



Pseudodon .\va (Theobald). 



Mandelay, Burma. 

 Monocondyla'a ai'a Theobald, Jl. As. Soc. Beng., XLII, Pt. 



2, 1873, p. 209, pi. XVII, fig. 15. 

 Pseudodon ava Simpson, Syn., 1900, p. 839. 



The description of this species is not accessible to me. I 

 am not certain that it belongs in this group. 



