FROM TANGANYIKA AND KENYA 143 



Remarks. The specimen now recorded, which is 17 mm. in diameter and 14 mm. 

 high, agrees so well with Dietrich's figure that there seems no doubt about its 

 specific identity. The spire of the shell is very obtuse, with slightly concave sides, 

 and the sutures are scarcely impressed. The last whorl is broadly rounded at the 

 periphery and the base is convex, quite uncoated with callus, and narrowly umbili- 

 cate. The outer lip is broken away, but the growth-lines are strongly prosocline. 

 The aperture, which occupied about five-sixths of the total height of the shell, was 

 evidently almost circular. The shell wall is thick and the surface quite smooth. 



This specimen appeared at first sight to belong to the genus Ataphrus, from which 

 it differs, however, in its open umbilicus. Dietrich, when describing C. staffi, com- 

 mented on its striking similarity to Ataphrus laevigatas (J. Sowerby) (cf. Hudleston 

 1894 : 349, pi. 29, figs. 5, 6), of the Inferior Oolite. The holotype was said to come 

 from Neocomian beds at a locality near Mikadi, Tanganyika, but the specimen now 

 recorded appears to be from an Upper Jurassic horizon. 



Family ATAPHRIDAE Cossmann 1918 



Genus ATAPHRUS Gabb 1869 



Ataphrus aff. actnon (d' Orbigny) 

 PI. 24, figs. 2a, b 



1850a. Aff. Trochns Actnon d'Orbigny : 265. 



1853. Aff. Trochns Acmon d'Orbigny : 278, pi. 314, figs. 1-4. 



1885. Aff. Ataphrus Acmon d'Orb. ; Cossmann : 281, pi. 7, figs. 9, 10. 



1894. A.ff. Ataphrus Acmon d'Orbigny ; Hudleston : 351, pi. 29, fig. 11. 



Material. One specimen (no. G. 26204). 



Locality and horizon. Kidugallo, Central Railway, Tanganyika ; Bajocian, 

 Station Beds. 



Remarks. This specimen, which is about 9 mm. high, agrees very well with the 

 figures of the European Bajocian species A. acmon cited above. Its last whorl and 

 aperture, however, are imperfect, so that it seems advisable to qualify its specific 

 determination. 



Genus TROCHOPSIDEA Wenz 1938 



Trochopsidea africana sp. nov. 

 PI. 24, figs. 5«, b, c, d 



Diagnosis. Shell small (diameter of largest specimen c. 7 mm.), turbiniform, 

 diameter exceeding height ; spire obtusely cyrtoconoid, its height almost equal to 

 that of the aperture. Whorls smooth, of moderate and even convexity, the last one 

 broadly rounded at the periphery. Base evenly convex ; no umbilicus. Inner lip 

 with moderatelv wide, grooved outer face, which is limited by a carina and is devoid 

 of a tubercle. 



