NO. 1205. sy.vorsis or TIII: \.\i.\i>r.*siMi'soN. 



9 Unio (Monocondijlcea] cambojensia SOWKIUJY, Conch. Icon., XVI, errata. 

 *Paeudodon cambojensis MORELKT, Ser. Conch., IV, 1875, p. 336. 



* Unio lamellatita HANLEY and THEOBALD, Couch. Intl., 1876, p. 5, pi. ix, fig. 6. 

 *Unio vaf/ulus FISCHER, Bull. Soc. Antnn., IV, 1891, p. 223. 



Siam. 



(Group of Hyriops-ix veMhuzeni.} 



Shell somewhat inflated, rather thin, rounded behind, winged; epi- 

 dermis dark brown with numerous green rays; nacre iridescent, bluish 

 white; anterior scars irregular, rather small; posterior scars rounded; 

 pseudocanlinals elongated, one in each valve, in the right valve there 

 is a secondary rudimental one; laterals elongate, urcuate, one ia the 

 right valve and two in the left. 



tHYRIOPSIS VELTHUZENI Schepman. 



* ITnio velthuzeni SCHEPMAN, Notes from Leyden Mas., XVII. 1895, p. 160, pi. iv, 



figs. 1, la' DROUET, Jl. de Concli., XLV, 1897, p. 124. 



Mandai River, Borneo. 



(Group of Hyriopsis schlegell.) 



Shell rather thin, slightly winged behind, narrowly rounded before 

 and angled at umbonial slope; posterior ridge high and rounded, beaks 

 rather low ; epidermis rough, blackish ; hinge line curved in front, 

 straight behind; pseudocardiuals generally entire; plications below the 

 laterals faint; nacre dull, lurid purplish or lead color. 



tHYRIOPSIS SCHLEGELI von Martens. 



* Unio schlegeli VON MARTENS, Mai. Blatt., VII, 1861, p. 55. *KOBELT, Abh. 



Senck, Nat. Ges., XI, 1879. p. 421, pi. xiv. * vox MARTENS, Nov. Conch., V, 

 1879, p. 192, pi. CLVIII, figs. 4, 5. * VON IHERING, Abh. Senck, Nat. Ges., 

 XVIII, 1893, p. 156. 



* Barbala scltleyeU P^TEL, Conch. Sam., Ill, 1890, p. 175, 



Japan. 



Subgenus CAUDICULATUS Simpson, 1900. 

 (Type, Unio caudiculatus von Martens.) 



Shell oval, inflated, slightly posteriorly winged, with a well-developed 

 posterior ridge, and above 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 unknown. 2 



HYRIOPSIS CAUDICULATUS Von Martens. 



* Unio caudiculatus VON MARTENS, Mai. Bl., XIV, 1866, p. 16. * SCHEPMAN, Notes 



Leyd. Mus., XVIII, 1896, p. 140.* DROUET, J. de Conch., XLV, 1897, p. 126. 



* Unio infraroatratus SCHEPMAN, Notes Leyd. Mus., XVII, 1895, p. 161, pi. iv, fig. 2. 



Borneo. 



'According to the photographic figure this shell very closely resembles Unio ala- 

 tus Say. 



I am in doubt as to the relationship of this species. 



