FROM TANGANYIKA AND KENYA 93 



Diagnosis. Of medium size (length of larger specimen c. 30 mm.), rectangular, 

 height two-thirds of length, beaks at about anterior third of length ; inflation slight. 

 Umbo very broad, not incurved ; postero-dorsal outline straight, horizontal, form- 

 ing a slightly obtuse angle with the straight or feebly convex posterior margin ; ven- 

 tral margin straight, parallel with postero-dorsal outline ; antero-dorsal outline very 

 slightly concave, gently inclined ; anterior margin of feeble convexity. Ornament 

 consisting of almost equidistant, well separated, erect lamellae, with fine growth- 

 threads in their intervals. 



Holotype and paratype. Holotype, no. LL.35045. One paratype only, no. 

 LL.35046. 



Locality and horizon. Didimtu hill, 2 miles S. of Bur Mayo, N.E. Kenya ; 

 Upper Lias, Toarcian, Didimtu Beds. 



Remarks. This species seems closely related to Astarte (Leckhamptonia) inter- 

 lineata Morris & Lycett, of the Bajocian and Bathonian of England, but it is much 

 larger. It bears some resemblance to the internal mould from the Upper Lias of 

 Germany figured by Roemer (1836 : 120, pi. 8, fig. 3) as "Corbis laevis Sow.? " and 

 re-named Astarte sublaevis by d'Orbigny. 



Genus COE LAST ARTE Boehm 1893 

 Coelastarte dietrichi sp. nov. 



J 933- Astarte (Coelastarte) cf. cotteausia (d'Orb.) de Loriol ; Dietrich : 42, pi. 4, fig. 61 (non 

 A. cotteausia d'Orbigny). 



Diagnosis. Shell of medium size (length of holotype c. 40 mm.), rectangularly 

 ovate, well elongated (length to height ratio 5:3), compressed. Beaks at about 

 anterior fifth of length, pointed, directed downward to some extent, with convex 

 dorsal margin rising above them ; antero-dorsal outline concave. Posterior margin 

 rounded except in earlier stages of growth, ventral margin flattened. Concentric 

 undulations strong and regular in earlier stages of growth, bending upward in a well- 

 defined angle posteriorly, irregularly spaced and rather weaker in later growth-stages. 



Holotype and paratype. The specimen figured by Dietrich, which it has not 

 been possible to examine, is designated as holotype. One specimen (no. L. 521 13) in 

 the material examined is the only paratype. 



Locality and horizon. Nitongola creek, Tendaguru, Tanganyika ; Upper 

 Kimmeridgian, " Trigonia smeei " Bed. The holotype came from the same horizon 

 in the bed of the Maimbwi river, Tendaguru. 



Remarks. This species was considered by Dietrich to be closely comparable to 

 Astarte cotteausia d'Orbigny as figured by de Loriol (1875 : 100, pi. 15, fig. 42) from 

 the Lower Kimmeridgian of France, but it is more elongated and has a more pro- 

 nounced convexity of the antero-dorsal outline. According to Cottreau (1929 : 101), 

 d'Orbigny's holotype of A. cotteausia is too ill-preserved to be worth figuring. 

 Astarte rzehaki Boehm (1883 : 558, pi. 62, fig. 33), Tithonian of Moravia, is higher at 



