CRANDIDU'RIA IO55 



A neat little species, which seems to show considerable 

 variation. The specimen first figured by Smith is decidedly 

 rayed; another fig-ured later by him in the P. Z. S. 1881, pi. 

 XXXIV, fig. 35, is rayless or nearly so. Four valves forming 

 two matched pairs of what I believe to be this are in the col- 

 lection of the National Museum and are formed exactly like 

 the figures of Smith and show a transition from the almost 

 smooth, rayed form, which is somewhat shining, to that which 

 is dull-colored, rayless and corrugated throughout. Specimens 

 from Ancey said to be labeled Unto hauttccauri by Bourguig- 

 nat are without doubt the above, and quite dififerent from 

 Bourguignat's species. 



Grandiuji'Ria smithi Bourguignat. 



Shell suboval, rather solid, subinflated or convex, inequilat- 

 eral ; beaks moderately elevated, turned forward, with fine, 

 subradial, somewhat zigzag sculpture; posterior ridge rounded, 

 ending in a decided but blunt point behind ; above it are two 

 dark, slightly raised, radiating ridges ; surface with concen- 

 tric, finely radial and zigzag, sub-nodulous sculpture; epider- 

 mis dull, pale brownish; pseudocardinals ragged; anterior 

 scars impressed ; nacre whitish to coppery-purple, and often 

 lighter colored at the edge of the shell. 



Length 32, height 24, diam. 14 mm. 



Lake Tanganyika. 

 Unio hurtoni Smith Cpart), Proc. Zool. Soc, 1881, pi. xxxiv. 



fig- 33«- 

 Grandidicria smithi Bourguignat, Bull. Soc. Mai. Fr., IL 



1885, p. 7. — Simpson, Syn., 1900, p. 829. 

 Unio burfoni var. sniiihi von Martens, Besch. Deuts. Ost-Af., 



1897, P- 238. 

 Grandidicria anceyi Bourguignat, Esp. Ouk. et Tan., 1885, 



p. 15; Icon. Moll. Tan., 1888, p. 43, pi. xix, figs. 4-6.— 



Simpson, Syn., 1900, p. 829. 



I am inclined to think with Bourguignat, who separated this 

 from hurtoni, that it is a valid species. A specimen in the 

 National Museum agrees very accurately with Smith's figure 



