FROM TANGANYIKA AND KENYA 119 



Description. This specimen is the internal mould of the right valve of a moder- 

 ately elongate Tancredia, 20-5 mm. long and n mm. high. The umbo lies at about 

 the posterior two-fifths of the length, and the slightly concave antero-dorsal outline 

 slopes rather steeply to the abruptly rounded anterior extremity of the shell. The 

 specimen is very much like the English Bajocian and Bathonian species T. angulata 

 Lycett, as figured by Morris & Lycett (1855 : 94, pi. 12, fig. 8 ; pi. 13, figs, ga, b). 



Tancredia manderaensis sp. nov. 

 PI. 19, fig. 1 



Diagnosis. Shell of medium size (length of holotype 22 ram., height 13 mm.), 

 moderately elongated, subequilateral. Antero-dorsal outline concave, sloping gently 

 to the rather sharply rounded anterior extremity of the shell. Ventral margin of 

 moderate convexity, the more strongly upcurved anteriorly. Posterior margin 

 weakly convex, slightly prosocline, forming an obtuse angle with the almost horizontal 

 postero-dorsal margin. Posterior diagonal ridge strong, delimiting a narrow, con- 

 cave posterior area. 



Holotype. No. LL.35190, consisting of the internal and external moulds of a 

 left valve. There is also a distorted specimen, possibly of the same species, in the 

 same piece of rock. 



Locality and horizon. Matasafara, 15 miles W. of Mandera, N.E. Kenya ; 

 uppermost Jurassic, Gudediye Beds. 



Remarks. Compared with the " Tancredia sp.A " of the Golberobe Beds (Oxfor- 

 dian) of N.E. Kenya and with the Tancredia from the Oxfordian of Cordebugle, 

 Calvados, France, figured by Chavan (1952 : 106, pi. 4, figs. 48-50) as Corbicella 

 (Corbicellopsis) autissiodorensis (Cotteau), this species is a little less elongated. It 

 is very close to the European Bathonian species T. extensa Lycett, as figured (under 

 the name T. axiniformis (Phillips)) by Morris & Lycett (1855, pi. 12, fig. 7 especially), 

 but has a more strongly convex ventral margin. 



Family QUENSTEDTIIDAE Cox 1929 



Genus QUENSTEDTIA Morris & Lycett 1855 



Quenstedtia saggersoni sp. nov. 

 PL 19, figs. 4, 6 



Specific name. After Mr. E. P. Saggerson, of the Kenya Geological Survey. 



Diagnosis. Of medium size, oblong, well elongated, with length (35 mm. in 

 holotype) exceeding twice the height ; only slightly inequilateral, with broadly 

 rounded, slightly protruding umbo just anterior to mid-length. Posterior margin 

 feebly convex, a little oblique in its general direction, joining the straight, parallel 

 postero-dorsal and ventral margins in even curves ; anterior margin strongly and 

 evenly convex. 



