1 18 JURASSIC BIVALVIA AND GASTROPODA 



generic diagnosis (the indistinctness of all the teeth except 26, 3a, Aii and Pi may be 

 partly due to the fact that it has been necessary to develop out the hinge region from 

 a hard limestone matrix in the specimens studied, but these teeth must have been 

 quite weak originally). 



Holotype and paratypes. Holotype, no. L.51995 ; numerous paratypes. 



Localities and horizons. Tingutitinguti creek (type-locality) and Kipande, 

 Tendaguru, Tanganyika ; Upper Kimmeridgian, " Trigonia smeei " Bed. Scarp at 

 Kindope, N. of Tendaguru ; Upper Kimmeridgian, Nerinella Bed. 



Remarks. Notwithstanding some external similarity to specimens from the 

 dinosaur beds of Tendaguru figured by Hennig (1914ft, pi. 14, figs. la-i) as Cyrena sp., 

 the hinge structure of the shells now described differs considerably from that of the 

 two valves represented in Hennig's pi. 14, figs. 2a, b. The form figured by Hennig 

 does not seem to be represented in the material examined by the present writer. 

 The Cyprina sp. of Dietrich (1933 : 46, pi. 8, fig. 125 ; pi. 11, fig. 147) seems to be 

 the Eomiodon dinosaurianum of the present memoir. 



Superfamily TELLINACEA 



Family TANCREDIIDAE Meek 1864 



Genus TANCREDIA Lycett 1850 



Tancredia sp. "A" 



PI. 19, fig. 2 



Material. One specimen (no. L. 93625). 



Locality and horizon. Korkai Hammassa, 19 miles E. of Takabba, N.E. 

 Kenya ; Oxfordian, Golberobe Beds. 



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

 ly elongate Tancredia, 22-3 mm. long and 11 mm. high. The umbo is slightly anterior 

 to mid-length, and just in front of it there is a slight concavity of the antero-dorsal 

 outline, which slopes at a rather gentle angle to the blunt anterior extremity of the 

 shell. It is close to the Tancredia from the Oxfordian of Cordebugle (Calvados) 

 figured by Chavan (1952, pi. 4, figs. 48-50) under the name Corbicella (Corbicellopsis) 

 antissiodorensis (Cotteau), but its anterior end is more tapering and sharply rounded 

 than in that species. It is also very similar to the English Bathonian species T. 

 extensa Lycett, figured under the name T. axiniformis (Phillips) by Morris & 

 Lycett (1855 : 93, pi. 12, fig. 7 ; pi. 13, figs. 6a, b), but its umbo is situated in a 

 slightly more anterior position. 



Tancredia sp. " B " 

 PI. 19, fig. 3 



Material. One specimen (no. L. 93614). 



Locality and horizon. Ogar Wein, 17 miles N.W. of Wergudud, N.E. Kenya ; 

 Oxfordian, Golberobe Beds. 



