PSEUDODON 1097 



Since the Synopsis was written the National Museum has 

 received three fine specimens of what are undoubtedly this 

 species from Sarawak, Borneo. The epidermis is reddish- 

 brown and shining, and there are traces of radial sculpture 

 on the anterior end of the shell. Above the corrugated area 

 on the dorsal slope there is a narrow, smooth zone reaching 

 to the ligament. The incremental striae are not very strong in 

 these shells. Walpole states that the basal margin is incurved 

 in the middle. The type is a little larger than the measure- 

 ments given above. 



Section Binf.uru.s Simpson, 1900. 



Biiicnrus Simpson, S}'n., kjoo, p. 839. 



Shell elongate rhomboid, thin, rounded in front, widely and 

 feebly biangulate behind, having two or more raised, radiating 

 lines on the posterior slope, which is slightly, obliquely wrin- 

 kled ; beaks low ; surface finely, irregularly, concentricallv 

 grooved : epidermis olive : teeth smooth, compressed ; nacre 

 bluish. Animal unknown. 



Type, Monocondylooa monhoti Lea. 



PsEUDODON MOUHOTi (Lea). 



Shell elongated, subrhomboid, slightly narrowed in front, 

 subcompressed, rather thin, inequilateral ; beaks subcompress- 

 ed, not prominent ; i^osterior ridge wide, rounded ; dorsal out- 

 line lightly curved ; anterior end rounded : base nearly or quite 

 straight ; dorsal slope obliquely truncated ; posterior end round- 

 ed below ; growth lines somewhat strong and irregular ; epi- 

 dermis greenish-brown often marked or shaded green on the 

 dorsal slope ; teeth small, rounded, subcompressed, single in 

 each valve ; nacre bluish, lurid purplish in the cavities, irides- 

 cent behind : muscle scars shallow. 



Length 67, height 34, diam. 18 mm. 



Cambodia ; Siam. 

 Man condyla:a moiihoti Lea. Pr. Ac. N. Sci. Phila., VH, 1863, 



p. 190. 

 Psendodon manhoti Cgnr.ad, Am. Jl. Conch., L 1865, p. 233. 



