ioo JURASSIC BIVALVIA AND GASTROPODA 



Locality and horizon. Usigiwa river, 6 miles W.S.W. of Kiwangwa, Bagamoyo 

 hinterland, Tanganyika ; Upper Oxfordian. 



Remarks. In few of the described Jurassic species of Fimbria do specimens 

 approach the present ones in size. De Loriol (1872 : 260 ; 1888 : 240, pi. 26, figs. 

 1, 2), however, has recorded some equally large specimens, from the Lower Kim- 

 meridgian of France and Switzerland, under the name Corbis buvignieri ; they differ 

 from the form now recorded in the absence both of the diagonal ridge and of radial 

 ornament. In Corbis jaccardi Rollier (1913 : 249, pi. 17, fig. 1), an equally large 

 form from the Upper Oxfordian of Switzerland, a diagonal ridge is present but the 

 shell is more elongate than in the African specimens, the concentric ribs are narrower, 

 and radial ornament is lacking. Corbis episcopalis de Loriol (1891 : 193, pi. 21, 

 figs. 2-4) bears radial ornament, but is much smaller than the specimens now 

 described and tapers less towards its posterior extremity. 



Fimbria sp. " C " 



PL 15, fig. 10 



Material. One specimen (no. LL. 35126), ex B.P. Coll. 



Locality and horizon. Lonji creek, W. of Mandawa, Tanganyika. Upper 

 Kimmeridgian. 



Remarks. This specimen is a broken and eroded left valve, about 53 mm. long, 

 with a broadly rounded umbo which is slightly posterior to median in position. 

 The ornament consists of broad, rounded, depressed ribs which are unequal in width 

 and separated by narrower intervals in which there are traces of radial threads. 

 The broadness of the ribs is a particularly noticeable feature. The form from the 

 Lower Kimmeridgian of Valfin, in the French Jura, described by de Loriol (1888 : 

 240, pi. 26, figs. 1, 2) as Corbis buvignieri Deshayes, and re-named Corbis canaliculata 

 by Rollier (1913 : 256), is comparable in this respect, but it is a larger shell and its 

 ribs are not quite so broad. It is most probable that the specimen now recorded 

 belongs to a new species. 



Genus SPHAERA J. Sowerby 1822 

 Sphaera subcorrugata Dietrich 

 1933. Corbis {Sphaera) subcorrugata Dietrich : 49, pi. 6, figs. 81, 82. 



Material. Two specimens (nos. L.51169, L.51891). 



Localities and horizons. N. of Kipande, near Tendaguru, Tanganyika ; 

 Upper Kimmeridgian, Nerinella Bed. 3 miles N.N.W. of Tapaira, near Tendaguru ; 

 Upper Kimmeridgian, " Trigonia smeei " Bed. 



