1374 ARTHROPTERON 



Braszaa coulhoisi Bourguignat, Un. and Ir. Tan., 1886, p. 



50; Icon., 1888, pi. XXIX, fig. I. — Simpson, Syn., 1900, p. 



907. 



The figure shows this shell to be somewhat ohovate and but 

 little elongated. Bourguignat states that it is bihiant. 



Brazz.^a ventrosa Bourguignat. 



Shell scarcely subsolid, greatly inflated, short, scarcely in- 

 equilateral, inequivalve, bihiant ; beaks low, but the umbonal 

 region is greatly swollen so that the outline of the shell from 

 an end view is heart-shaped ; dorsal line nearly straight ; ante- 

 rior end evenly rounded ; base curved ; posterior end beaked ; 

 surface violet-chestnut ; nacre uniform violet wine-color, bril- 

 liantly iridescent. 



Length 64, height 41, diam. 37 mm. 



Lake Tanganyika. 

 Bras;:cca ventrosa Bourguignat, Un. and Ir. Tan., p. 45 ; Icon., 



1888, pi. XXIX, fig. 4. — Simpson, Syn., 1900, p. 907. 



This species should be distinguishable by the immense, 

 rounded umbonal region, the beaks themselves being flattened. 



The following are unfigured species : 

 Braszcea rondahcli Bourguignat, Un. and Ir., 1886, p. 46. 

 Braz::cEa nioineti Bourguignat, Un. and Ir., 1886, p. 47. 

 Brn.zzcua jonrdyi Bourguignat, Un. and Ir., 1886, p. 48. 

 Braz:~<Ta charbonnieri Bourguignat, Un. and Ir., 1886, p. 52. 

 Braszcea lavigerina Bourguignat, Un. and Ir., 1886, p. 53. 

 Brazscea bridoiiivi Bourguignat, Un. and Ir., 1886, p. 54. 

 Brazzcea nczvcoiubiana Bourguignat, Un. and Ir., 1886. p. 55.. 



All from Lake Tanganyika. 



Genus ARTHROPTERON Rochebrune. 



Arthropteron RociiEr.RUNE, Bull. Mus. Hist. Nat., 1904, p. 



460. 



"Shell ovoid, somewhat thick, quite inflated, abruptly round- 

 ed in front, subelongate behind, edentulous ; umbones subcon- 

 tiguous, small ; ligament long, curved, partly covered ; in the 

 region behind the beaks forming an area like a pen. concave, 



