﻿PILSBRYOCONCHA 241 



sinulus small, obtusely angled ; nacre bluish, changing to reJ 

 towards the beaks; muscular impressions shallow. 



Long 88 ; alt. vert. 42.5, alse 6\, diam. 36 mm. Beaks at 1-3 

 of the length." (von Martens). 



Type locality, Tonkin. 



Anodonta siiilla von Marteivs, Nachr. Deutsch. Mai. Ges., 

 1902, p. 130. 



"In profile, it reminds one most of An. lingiuceformis More- 

 let, which Simpson refers to Pilsbryoconcha, but it is much 

 more inflated, the beaks are less polished, with strong, irreg- 

 ular, almost ridge-like lines of growth. From An.' jondyi 

 Morlet, which was collected by Fruhstorfer in Phuc-Son, An- 

 nam, it is easily distinguished by its straight basal margin and 

 more angulated, projecting anterior margin." 



P11.SBRYOCONCHA Exius (Lea). 



Shell long obovate, thin, compressed, narrowed and evenly 

 rounded in front, slightly winged behind, the dorsal line 

 straig-ht; posterior ridge low, widely rounded or feebly bian- 

 gulate, with a shallow radial furrow above it; beaks com- 

 pressed, their sculpture consisting of delicate ridges, which 

 run nearly parallel with the dorsal line ; post-basal region con- 

 siderably produced and widely rounded ; posterior point rather 

 sharp, mid-way up from the base; growth lines irregular, 

 somewhat sulcate at the outer edge, the posterior slope hav- 

 ing numerous delicate folds, which follow the growth lines; 

 epidermis pale brown, smooth ; hinge a mere line, edentulous 

 or sometimes having a single, low, smooth anterior tooth or 

 prominence in each valve ; beak cavities very shallow, with two 

 or three scars ; adductor scars very indistinct ; nacre brilliant 

 richly iridescent. 



Length 85, height 43, diam. 15 mm. 



Southeastern Asia, Sumatra, Java. 

 Anodonta exilis Lea, Tr. Xm. Phil. Soc.VL 1839, p. 81, pi. 



XXII, fig. 68; O'bs., II, 1838, p. 81, pi. xxii, fig. 68.— Cles- 



siN, Conch. Cab. Ano.. 1875, P- 171. pl- i-vi, figs. 6-8. 

 Margarita (Anodonta) e.vilis Lea, Syn., 1838, p. 32. 



