1076 STMPSONKI.LA 



(Jnio serradeUi Droukt, Jl. de Conch., XL. 1892, p. 86. 

 Dalliella scrradcUi Simpson, Syn., IQOO, p. 834. 



Evidently a S'impsonclla and quite probably synonymous 

 with some of the species already described. So far as I know 

 it has never been fig"ured. If the outline is really ovate as is 

 claimed in the description, it may be a valid species. 



Group of SimpsoneJla iusiilaris. 



Shell subsolid, subrhomboidal, biangulate behind ; pseudo- 

 cardinals and laterals blurred, not greatly compressed; nacre 

 lurid, tinged purplish. 



SlMPSONI^LI^A INSULARIS (DrOUCt). 



Shell long rhomboid, inequilateral, slightly narrowed and 

 rounded in front, subcompressed, subsolid ; beaks not promi- 

 nent ; dorsal line lightly curved ; basal line nearly straight ; 

 dorsal slope obliquely truncate ; posterior ridge moderate, 

 somewhat double, ending below the median line in a feeble 

 biangulation ; surface with strong, sulcate, concentric sculp- 

 ture ; epidermis brown, not shining ; vestigial pseudocardinals 

 and laterals present ; nacre lurid. 



Length 48, height 30, diam. 15 mm. 



Borneo; Palawan Island, Philippines. 

 Pseudodoii insularis Drouet, Rev. Biol. Fr., \l, 1894, p. 217, 



fig. 2. 

 Dalliella insularis Simpson, Syn., 1900, p. 834. 

 Prcssidens insularis Haas, Nachr. Deutsch. Mai. Ges., 1910, p. 



103; Conch. Cab., Unio, 1912, pi. 23, figs. 1-2. 



Close to S. crassa, but appears to be smaller, not quite so 

 much elongated, more compressed, more strongly, concen- 

 trically sculptured and duller-colored. I have seen one young 

 shell and an adult valve of what I take to be this species, from 

 Palawan Island, belonging to the collection of Mr. Berlin H. 

 Wright. These have somewhat zigzag sculpture, perfect lat- 

 erals and moderately developed pseudocardinals. 



According to Haas. (1. c), this species belongs to his new 

 genus Pressidens. 



