FROM TANGANYIKA AND KENYA 101 



Genus SPHAERIOLA Stoliczka 1871 



Sphaeriola madridi (d'Archiac) 

 PL 16, figs. 3, 4 



1843. Cardium madridi d'Archiac : 373, pi. 25, figs, ja, b. 



1867. Corbis (Sphaera) madridi (d'Archiac) ; Laube : 38, pi. 3, fig. 4. 



1921. Unicardium (Sphaeriola) madridi (d'Archiac) ; Cossmann, pi. 3, figs. 14, 15. 



1948. Sphaeriola madridi (d'Archiac) ; Cox & Arkell : 35. 



Material. Several specimens. 



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

 Callovian], Asaharbito Beds. 



Remarks. These specimens do not appear to be distinguishable from S. madridi. 

 The concentric corrugations which form their ornament are somewhat unequal and 

 irregularly distributed, much as in the specimens figured by Laube. It is probable 

 that the regularity of their arrangement in d'Archiac's original figure is due to their 

 inaccurate representation by the artist. It has not been possible to expose the 

 hinge-teeth in any of the African specimens and to confirm that the dentition is that 

 of a Sphaeriola rather than of the externally similar genera Mactromya and Uni- 

 cardium. A fragment of an internal mould in the material studied shows, however, 

 traces of crenulations of the ventral margin, such as are found in Sphaeriola and not 

 in the other two genera. The identification of Sphaeriola is important stratigraphi- 

 cally, as the known range of the genus is from Lias to Callovian and it is particularly 

 abundant in the Bathonian. 



Superfamily CARDIACEA 



Family CARDIIDAE Goldfuss 1820 



Genus PROTOCARDIA Beyrich 1845 



Protocardia africana sp. nov. 

 PL 16, figs. 2a, b, c 



19086. Protocardia cf. striatula Sow. ; Thevenin : 27, pi. 4, fig. 5. 



Diagnosis. Of small-medium size (length of largest specimen 21 mm.), suborbi- 

 cular, equilateral, height slightly less than length, shell evenly and strongly inflated. 

 Umbones rather narrowly rounded, prominent, well incurved to the very slightly 

 prosogyrous beaks. Margins forming a strongly convex and uninterrupted curve ; 

 anterior end of shell only slightly less broad than posterior end. No diagonal ridge. 

 Flank unornamented except for growth-lines ; posterior area not flattened, with 

 about 30 granose radial riblets. 



Holotype and paratypes. Holotype, no. LL.35603. Several paratypes (nos. 

 LL.35063-72). 



