FROM TANGANYIKA AND KENYA 115 



Remarks. Newton's holotype of Astarte? baroni, from Madagascar, is so ill- 

 preserved that when describing the specimens from India (Cox 1935ft : 7, pi. 1, figs. 

 17-19) upon which I founded the genus and species Eomiodon indicus I did not 

 recognize their generic affinity with it. Examination of further material from 

 Madagascar has left me with no doubt on this point. The two forms are similar in 

 size and outline, but E. indicus is much more strongly inflated than any specimens of 

 the Madagascan species which I have examined, and it is doubtful if they should be 

 placed in synonymy. 



Of the specimens now recorded fom Tanganyika, those from Ngerengere are quite 

 typical. Those from the locality near Kidugallo, only two in number, are relatively 

 small, the larger being only 19 mm. long, and the relatively wide-spaced concentric 

 ridges of the earlier growth-stages are replaced by closely spaced ridges at a shorter 

 distance from the umbo than in typical specimens. They could possibly belong to a 

 distinct species or subspecies, but there is insufficient material for a decision to be 

 reached on this point. 



Eomiodon tanganyicensis sp. nov. 

 PI. 18, figs. 12a, b, 13 



Diagnosis. Of medium size (length of holotype c. 27 mm.), cuneiform, moderately 

 inflated. Umbones anteriorly placed but not quite terminal, well incurved to the 

 strongly prosogyrous beaks. Postero-dorsal outline strongly convex anteriorly, less 

 convex posteriorly, sloping to the low, subangular posterior extremity of the shell. 

 Ventral margin strongly convex, merging anteriorly with the convex anterior mar- 

 gin ; antero-dorsal outline slightly concave. Escutcheon not distinctly bordered 

 by a ridge. Surface of shell without marked concentric ornament. 



Cardinal teeth consisting, in left valve, of stoutly triangular, anteriorly directed 

 anterior tooth (2b) very close to antero-dorsal margin, and of a quite strong, elongate 

 posterior tooth (4ft) widely divergent from 2b ; in right valve, of stout, triangular, 

 mesially placed tooth (3ft) and narrow, weak anterior tooth (3a). Right valve with 

 strong, lamelliform posterior lateral tooth (Pi) and a weaker, lamelliform anterior 

 lateral (Ai), each separated from shell margin by a recess for the reception of a lateral 

 tooth formed by a projection from the corresponding part of margin of left valve. 



Holotype and paratypes. Holotype, no. LL.7215. About 20 paratypes. 



Locality and horizon. Quarries N.N.E. of Ngerengere, Central Railway, Tanga- 

 nyika ; Bajocian (?). 



Remarks. The specimens are encrusted with fine sandy material, but their lack 

 of concentric ornament appears to be an original feature and to distinguish them 

 from E. baroni. The lack of an angular ridge bordering an escutcheon is another 

 point of difference. They are less gibbose than E. baroni, but it is not possible to 

 say if this difference is entirely due to the compression which most of them have 

 undergone. Their dentition is that of a typical Eomiodon. 



