﻿2l8 IIVKIOI'SIS 



Suhiicnus Caudicu[.atus Simpson, 1900. 



Caudiciilatiis Simi'Son, Syn., 1900, p. 581. 



Shell oval, inflated, slig^htly posteriorly winged, with a well- 

 developed posterior ridge and ahove it a deep, wide furrow 

 ending in a broad, well-defined notch on the posterior slope; 

 one pseudocardinal in the right valve and two in the left ; two 

 laterals in the left valve and one in the right. Animal un- 

 known. 



Type. Unio candiculatus von Martens. 



Hyriopsis caudicui,at.\ (von Martens). 



Shell oval, much inflated, very inequilateral, rather smooth, 

 with only slight wrinkles and numerous fine, concentric striae; 

 beaks prominent, decorticated in the specimens examined ; epi- 

 dermis dark brown with a metallic luster, somewhat velvety 

 near the extremities ; upper margin slightly curved posteriorly, 

 straight anteriorly ; anterior margin rounded, passing insensi- 

 bly into the convex ventral margin ; posterior margin oblique 

 above, with an obtuse angle near the superior one ; somewhat 

 below the middle of its length it is deeply and widely emargin- 

 ate ; posterior end widely truncated ; from the edges of this 

 truncation two low posterior ridges run towards the beaks ; 

 nacre blue, iridescent near the f^ee margins, olive-yellow near 

 the beaks ; hinge strong ; teeth irregular, thick ; there is a cren- 

 ulated pseudocardinal in the right valve and two nearly con- 

 solidated ones in the left ; two nearly straight laterals in the 

 left valve and one in the right; anterior scars irregular, deep; 

 posterior scars shallow ; pallial line distinct. 



Length 67, height 47. diam. 29 mm. 



Small brook near Singangi in the Ketoengau District, 

 Borneo. 



Unio caudictilatus von Martens, Mai. Bl., XIV, 1866, p. 16. 

 Unio infrarostrahis Schepman, Notes Leyd. Mus., XVII, 



1895, P- 161, pi. IV, fig. 2. 

 Hyriopsis candiculatus Simpson, Syn. 1900, p. 581. 

 Caudicalatus candiculatus Haas, Conch. Cab., 1912, pi. 18, 



fig. I. 



I have never seen this species and have considerable doubt 

 as to its relationship. It is placed in Hyriopsis provisionally. 



