I 164 UKCTinivNS 



rostrum. Beaks situated at j4 of the length, low, deeply 

 eroded, not approachmg ; areola narrow, almost lanceolate ; 

 posterior slope compressed, margined by the distinct posterior 

 ridge; ligament narrow, (luite long. Hinge with a thin, nar- 

 row lateral and two, elongate, curved, lamelliform, equal 

 cardinal teeth in the right valve, one cardinal and an obsolete 

 posterior accessory tooth in the left, the long laterals forming 

 an angle with the cardinals ; muscular and pallial impressions 

 not very strong; nacre bluish-white, somewhat livid under the 

 umbones. 



Length 43. height 17.5, diam. 11 mm. (_Strubell). 



Type locality, South Sumatra. 

 Unio palciubangensis Strubell, Nachr. Deutsch. Mai. Ges., 



1897, p. 10. — Simpson, Syn.. 1900, p. 862. — Haas, Conch. 



Cab., Unio, 1912, pi. 27, fig. 7. 



Haas, (1. c), considers this a synonym of Rcctidens gracilis. 



Var. pahumbaensis (von Martens). 



"Differs by the shorter and posteriorly more elevated form, 

 as well as that the posterior ridge very soon disappears, so that 

 it is distinctly seen only in the umbonal. region. The rostrum 

 of this form is like that of the typical form, somewhat declined, 

 owing to the fact that the dorsal margin is oblique, while the 

 basal margin is almost straight, while in the closely related, 

 U. sninatrcnsis Dunk., the posterior margin descends almost 

 as much as the basal ascends, so that the rostrum points back- 

 ward. 



Length 53, height at beaks 19, at wing 23, diam. 13 mm. 



Beaks situated at Y^. of the length." (von Martens). 



Type locality not given. 

 Unio palemhangensis var. pahumbaensis xon Martkns, Nachr. 



Deutsch.- Mai. Ges., 1900, p. 14. 

 Unio paliocnibacnsis Haas, Conch. Cab., Unio, 1912, pi. 28, 



figs. 1-2. 



Haas, (1. c), considers this a synonym of Rcctidens (/racilis. 



