120 JURASSIC BIVALVIA AND GASTROPODA 



Holotype and paratype. Holotype, no. L.93600. One paratype, no. L.93636. 



Localities and horizon. Ogar Wein, 17 miles N.W. of Wergudud, N.E. Kenya 

 (type-locality) ; Korkai Hammassa, 19 miles E. of Takabba, N.E. Kenya ; both 

 Oxfordian, Golberobe Beds. 



Remarks. This species is rather closely comparable to Q. elongata Hudleston, an 

 English Oxfordian species figured by Arkell (1934a : 298, pi. 40, figs. 6, 7), but is not 

 quite so inequilateral. It is more elongate and less inequilateral than Q. laevigata 

 (Phillips), another Oxfordian species figured by Arkell (1934a : 296, pi. 40, figs. 4, 5). 



Quenstedtia jouberti sp. nov. 

 PI. 19, fig. 5 



i960. Quenstedtia sp ; Joubert, pi. 10, fig. 1. 



Specific name. After Mr. P. Joubert, of the Kenya Geological Survey, collector 

 of the holotype. 



Diagnosis. Moderately large for the genus (length of holotype 60 mm. -f), 

 rather pronouncedly inequilateral ; umbones broadly rounded, projecting very 

 slightly above dorsal margins, and placed at anterior third of length. Postero-dorsal 

 margin straight, forming an obtuse angle with posterior margin, which merges with 

 ventral margin in a broad curve ; ventral margin straight, diverging slightly from 

 postero-dorsal margin in a posterior direction ; antero-dorsal outline moderately 

 excavated ; anterior margin (damaged in holotype) apparently evenly rounded. 

 An obtuse ridge runs from the umbo to the postero- ventral corner of the shell. 



Holotype. No. L. 92213. The only specimen. 



Locality and horizon. N. of Figfirya, northern Raiya hills, N.E. Kenya ; 

 Upper Kimmeridgian, Dakacha Limestones. 



Remarks. This species is less elongate and more strongly inequilateral than Q. 

 gortanii Venzo (1949 : 159, pi. 16, fig. 27), the most closely comparable of the five 

 representatives of the genus described by this author from the late Jurassic beds at 

 Cud Finagubi, in northern Kenya. It is much more inequilateral than the English 

 Portlandian species Q. portlandica Cox (1929 : 191, pi. 6, figs. 5, 6). 



Superfamily MYACEA 



Family CORBULIDAE Gray 1823 



Genus CORBULA Bruguiere 1797 



Corbula didimtuensis sp. nov. 

 PI. 19, figs. 10, ii«, b, c 



Diagnosis. Moderately large for the genus (length of largest specimen 24 mm.), 

 subrectangular with a triangular tendency, very slightly inequilateral, not rostrate 

 posteriorly ; height two-thirds to three-quarters of length ; beaks slightly anterior 



