io 4 JURASSIC BIVALVIA AND GASTROPODA 



consobrina has been recorded from Madagascar by Douville and others, while Dacque 

 (1910 : 30) has recorded a " Cardium sp. ", said to resemble this species, from Callo- 

 vian beds at Km. 127 along the railway from Dar-es-Salaam to Morogoro. 



Protocardia rahmuensis sp. nov. 

 PI. 17, figs. 4«, b 



Diagnosis. Of medium size (length of holotype c. 20 mm.), suborbicular, length 

 and height almost equal, rather strongly inflated. Umbo prominent, median, with 

 strongly convex outline. Antero-dorsal outline well excavated, anterior and vent- 

 ral margins forming an even curve of strong convexity ; posterior margin slightly 

 less convex than anterior one and forming a rather ill-defined, obtuse angle with 

 ventral margin ; level of postero-dorsal margin slightly higher than that of antero- 

 dorsal margin. Posterior area separated from flank by obtuse ridge and bearing 

 nearly 20 radial riblets. Traces of fine concentric ridges preserved on flank of shell. 



Holotype. No. L. 92257, an internal mould. One or two further specimens are 

 ill-preserved and should scarcely rank as paratypes. 



Localities and horizon. River section W. of Rahmu-El Wak road, 5^ miles 

 S.W. of Rahmu (type-locality) ; Uacha, 6 miles S. of Rahmu, S.E. Kenya : both 

 Oxfordian, Rahmu Shales. 



Remarks. The most closely comparable European Oxfordian species is Proto- 

 cardia intexta (Minister), illustrated in a number of standard monographs by figures 

 many of which have been subsequently re-named. In P. roemeri Rollier (for Cardium 

 intextum Roemer (1839, P L J 9> n S- 3 > a l so de Loriol 1897, pi. 12, fig. 10)) the antero- 

 dorsal and postero-dorsal outlines of the shell are less strongly excavated. Proto- 

 cardia valbertensis de Loriol (1901 : 61, pi. 4, figs. 12-14), which Roeder (1882 : 89, 

 pi. 3, figs. 4<z-c) had figured as P. intexta, closely resembles the African species in 

 outline and ornament, but is much smaller. A poorly preserved Protocardia of 

 about the same size which occurs commonly in the Golberobe Beds (Oxfordian) has 

 a less prominent umbo and appears to belong to a different species. 



Protocardia schencki Muller 

 PI. 17, figs. 5«, b 



1900. Protocardia schencki Muller : 544, pi. 19, figs. 12, 13. 

 19146. Protocardia schencki Muller ; Hennig : 170. 

 !933- Protocardia schencki Muller ; Dietrich : 52. 



Material. Numerous specimens. 



Localities and horizons. Scarp and stream bed at Kindope, N.N.W. of 

 Tendaguru, Tanganyika ; Upper Kimmeridgian, Nerinella Bed. Tingutitinguti 

 creek, Nitongola creek, and Kindope river, all near Tendaguru, Tanganyika ; Upper 

 Kimmeridgian, " Trigonia smeei " Bed. Kinjele, 5 miles W. of Mtapaia, N. of 

 Tendaguru, Tanganyika ; Upper Kimmeridgian, Indogrammatodon Bed. 



