1322 SPA'niA 



Spatlia rrlstis Joijsseaumc, Bull. Soc. Zool. Fr., XI, 1886, p. 



497. — Simpson, Syn.. 1900, p. 897. 

 Spatha rochchrunci Jousseaume, Bull. Soc. Zool. Fr., XI, 



1886. p. 494, pi. XIV, figs. I, la. — Gekmaix, Arch. Zool. Exp. 



et Gen., (5), I, 1909, p. 56. 



A rather small species with a dark, somewhat lurid, sub- 

 shining surface, the epidermis showing traces of radial and 

 feather-like wrinkling. The nacre is a peculiar combination of 

 tints, and though lurid, is shining. 



Germain, (1. c), refers S. rochehninei JousS. to chaiziana 

 Rang as a synonym. 



Spatha trapezia von Martens. 



Shell somewhat irregularly obovate, inflated, solid ; some- 

 what inequilateral ; beaks scarcely elevated ; posterior ridge 

 rather full, narrowly rounded, curved, ending a little below the 

 median line in a blunt point ; dorsal outline curved ; anterior 

 end rounded, slightly narrowed ; base curved and fuller behind 

 the middle ; posterior end obliquely subtruncate above ; surface 

 nearly smooth ; epidermis greenish, brownish posteriorly ; na- 

 cre bluish-white. 



Length 70. height 39, diam. 22 mm. 



Length 66, height 35.5, diam. 26 mm. 



Lake Victoria Nyanza. 

 Spatha trapezia von Martens, Besch., 1897. p. 243, fig. — 



Simpson, Syn.. 1900. p. 879. 



Solider and more obovate than S. tristis, having a some- 

 what elevated, curved posterior ridge. It is more produced 

 behind the middle of the base than that species and has a 

 bluish-white nacre. 



Var. senilis von Martens. 



The variety senilis seems like a stunted form of the above. 

 The posterior point is somewhat drawn down and the shell 

 is smaller than the type. 



Length 58, height ^^, diam. 20 mm. 

 Spatha trapezia var. senilis von Martens, Besch., 1897, p. 244. 



— Simpson, Syn.. 1000. p. 879. 



