86 JURASSIC BIVALVIA AND GASTROPODA 



Astarte pindiroensis sp. nov. 



PL 13, figs. 4a, b, 5«, b 



Diagnosis. Small (length of holotype 5-5 mm ; of largest paratype 11 mm.), 

 rectangularly ovate, height from four-fifths to five-sixths of length, inflation mode- 

 rate. Inequilateral, umbones situated from anterior quarter to third of length, 

 scarcely incurved, directed anteriorly, their outline continuous with the feebly con- 

 vex, gently sloping to sub-horizontal postero-dorsal outline of the shell, which merges 

 in a broad curve with the feebly convex, only slightly oblique posterior margin ; 

 ventral margin moderately convex, forming a rounded-off, obtuse angle with poste- 

 rior margin and merging in an even curve with the broadly convex anterior margin ; 

 concavity of antero-dorsal outline confined to neighbourhood of beak. No diagonal 

 ridge. Escutcheon very narrow, bordered by blunt umbonal ridges ; lunule an un- 

 impressed cordiform area limited by faint striae. Ornament consisting of fine con- 

 centric threads, slightly unequal and irregularly arranged in places. 



Holotype and paratypes. Holotype, no. LL.35206, figured paratype, no. 

 LL. 35207, both extracted from a piece of limestone containing a large number of 

 other paratypes. 



Locality and horizon. Tributary of Namakumbira stream, 1 mile S.E. of 

 Nkomore, Mandawa-Mahokondo area, Tanganyika ; Bajocian (?), Pindiro Shales. 



Remarks. This species is smaller and less trigonal than A . kenti, described above. 

 Its very fine ornament distinguishes it from the European Bajocian form A. minima 

 Phillips. 



Astarte ayersi sp. nov. 

 PI. 13, figs, ya, b 



Specific name. After Mr. F. M. Ayers, of the Kenya Geological Survey. 



Diagnosis. Rather small (length of holotype 15 mm.), triangularly subovate, 

 slightly longer than high, evenly and fairly strongly inflated. Umbo prominent, 

 narrowly rounded in outline, placed at about anterior third of length. Antero- 

 dorsal outline slightly convex, sloping gently, and forming a rounded-off, obtuse 

 angle with posterior margin ; posterior, ventral and anterior margins forming an 

 even curve which is almost a semicircle : antero-dorsal outline strongly excavated. 

 Ornament consisting of narrow, evenly spaced concentric ridges about 075 mm. 

 apart in later growth-stages. 



Holotype and paratypes. Holotype, no. L. 83876 ; numerous paratypes, 

 mainly imperfect. 



Locality and horizon, i mile N. of Asaharbito, N.E. Kenya ; Bathonian [? or 

 Callovianl, Asaharbito Beds. 



Remarks. This species bears some resemblance to the European Bathonian 

 species Astarte oolitharum Cossmann (1925 : 663, pi. 22, figs. 14, 15) (= A. depressa 

 Morris & Lycett 1855, pi. 9, fig. 11, non Goldfuss), but is considerably larger. The 



