FROM TANGANYIKA AND KENYA 105 



Remarks. This is a small, orbicular, equilateral Protocardia, most specimens of 

 which are evenly inflated, although a few have an obscure diagonal angulation. The 

 largest specimens are about 15 mm. long. In one specimen which retains some of its 

 original shell it can be seen that there are 15 or more riblets on the posterior area and 

 that in earlier stages of growth these form a delicate reticulate pattern with closely 

 arranged growth-threads. 



Protocardia suprajurensis (Contejean) 

 PI. 17, fig. 6 



i860. Cardium suprajurense Contejean : 276, pi. 14, figs. 11, 12. 



1875. Cardium suprajurense Contejean ; de Loriol : 61, pi. 13, fig. 43. 



1878. Cardium suprajurense Contejean ; Struckmann : 94, pi. 4, figs. 5, 6. 



1905. Protocardia suprajurensis (Contejean) ; Schmidt : 173. 



Material. One specimen (no. LL.35I34), ex B.P. Coll. 



Locality and horizon. N. of Matapwa, Pindiro area, Tanganyika ; Upper 

 Kimmeridgian. 



Remarks. The specimen consists of one valve of a subequilateral, moderately 

 and evenly inflated representative of the Cardiidae, the height of which (c. 29 mm.) 

 is approximately equal to the length. It is devoid of ornament except in later stages 

 of growth, in which there are low, round-topped concentric ribs slightly more than 1 

 mm. wide, separated by narrow intervals. No trace of radial ribbing can be seen on 

 the posterior part of the surface, which, however, is rather obscured by matrix. 



This specimen seems to belong to Protocardia suprajurensis, a Kimmeridgian form 

 originally described from the French Jura, where specimens attain about the same 

 size. The affinities of the species have been disputed, Brauns having considered it 

 to belong to Anisocardia. De Loriol and Struckmann, however, have expressed the 

 opinion that it is a true cardiid, and it seems to be related to a group of species found 

 in the Lower Cretaceous and similarly ornamented with concentric ribs. This group 

 includes Cardium rothpletzi Dietrich, from the Neocomian of Tendaguru and C. 

 sphaeroideum Forbes, from the Aptian of England, both of which attain a consider- 

 ably larger size. Dietrich referred C. rothpletzi to his subgenus Tendagurium, but 

 it does not appear to be closely related to the type-species of that taxon, and it is 

 here included in Protocardia, sensu lato. 



Subgenus TENDAGURIUM Dietrich 1933 



Protocardia (Tendagurium) bannesiana (Contejean) 



i860. Cardium bannesianum {ex Thurmann, MS.), Contejean : 276, pi. 15, figs. i-$. 



1862. Cardium banneianum Thurmann ; Thurmann & Etallon : 181, pi. 22, figs. \a, b. 



1872. Cardium banneianum Thurmann ; de Loriol : 249, pi. 15, figs. 1, 2. 



1897. Cardium banneianum Thurmann ; Futterer : 600. 



1912. Nemocardium banneianum Thurmann ; Lissajous : 91, pi. 11, fig. 10. 



1930. Cardium banneanum Etallon ; Basse : 140, pi. 5, fig. 8. 



i960. Cardium (Protocardia?) bannesium Contejean ; Joubert, pi. io, fig. 6b. 



