io8o 



rPElTDODON 



All that is known of the animal is the figure, without descrip- 

 tion, of Deshayes and Jullien of P. morcleti. From the char- 

 acter of the shells I am inclined to believe that they are closely 

 related to those of SimpsoncUa. though I have been unable 

 to examine any specimens that gave any clue to the beak 

 sculpture. I am not certain that all the species I have placed in 

 Pseiidodon should go there. 



Knv TO srEciES or Pseudodon. 



Shell somewhat elongated. 

 Inflated. 



Rather thin. nankin gensis. 



Subsolid. sccundus. 



Not inflated. 



Blackish, folded on dorsal slope. loomisi 



Brownish. salwenianus. 



Green-tinted, scarcely convex. mouhoti. 



Tawny, convex. exilis. 



Compressed. solidiis. 



Shell not elongated. 



Triangular or subtriangular. camhodjcnsis. 



Subrhomboid. 



Strongly, concentrically sulcate. 



Inflated. chaperi. 



Convex or subcompressed. crebristriatus. 



With folds on the dorsal slope. harmandi. 



Nearly smooth or merely concentrically striate. 

 Shell inflated ; dorsal ridge high, aureus, 



ivalpolei. 



Compressed or merely convex, resupinatus, mieolus, 



cmnm.gii, vondemhuschianus, zollingeri, ovalis. 



Subinflated. inoscidaris, peguensis. 



Inflated, large. moreleti, pondcrosus. 



Obovate, subinflated. bicnstatus, thomsoni. 



Oval. 



Inflated. tumidm., 



Subcompressed or convex. ellipticus, 



Suborbicular. orbicularis. 



