GRANDIDIERIA IO59 



Grandidieria caliista Bourguignat. 



Shell somewhat elongated, irregularly ovate, scarcely inflat- 

 ed, slightly inequilateral ; beaks very full and high ; posterior 

 ridge strong, double, ending at or below the median line in a 

 slight biangulation ; the anterior and posterior ends both 

 drawn out and much narrower than the middle of the shell ; 

 anterior end rounded, subangular above and below ; posterior 

 end slighty angled above and below ; the base line is very full 

 and rounded just behind the middle; surface covered with zig- 

 zag-radial and subnodulous sculpture. 



Length 22, height 14, diam. 9 mm. 



Lake Tanganyika. 

 Grandidieria caliista Bourguignat, Icon. Moll. Tan., 1888, p. 



43, pi. XIX, figs. 13-15. — Simpson, Syn., 1900, p. 829. 



A most singularly shaped shell, being high and full in the 

 middle and drawn out into a sort of beak at each end. It is 

 quite probable that the specimens figured are somewhat dis- 

 torted G. rhynchoneUa, though that species is apparently much 

 smoother. Unfortunately I do not have access to any original 

 material of this and two other species of this group, which are 

 figured in Bourguignat'^ Iconographie. 



Grandidieria gtraudi Bourguignat. 



Shell decidedly and irregularly long rhomboid, scarcely in- 

 flated, inequilateral ; beaks sharp, subcompressed and but little 

 elevated ; anterior end broadly rounded, subangulate above ; 

 base line full below and just in front of the beaks, greatly in- 

 curved towards the posterior end ; posterior ridge double, 

 rather wide, much curved, close to and parallel with the dor- 

 sal outline, ending at the base of the shell in a long, drawn 

 out, biangulate beak, which curves downward in a remarka- 

 ble manner ; surface curved with fine, zigzag-radial, subgran- 

 ulous sculpture. 



Length 28, height t8, diam. 11. 5 mm. 



Lake Tanganyika. 

 Grandidieria girandi Bourguignat, Nat. Prod., 1885, p. 95. — 



Simpson. Syn., 1900, p. 830. — Gei^main, Moll. Soc. Tang., 



1908, p. 683, figs. 33-34. 



