FROM TANGANYIKA AND KENYA 09 



of the first of these species, which may be recorded as " species A ", is about 60 mm. 

 long. The ornament consists of closely and irregularly arranged concentric ridges, 

 the average distance between which varies to some extent in different specimens but 

 is always well below 1 mm. No trace of radial ornament can be detected. This 

 form is less inflated than F. lajoyei (d'Archiac) (1843 : 372, pi. 27, figs, la-d), from 

 the Bathonian of north-western Europe, and differs further in the closer arrange- 

 ment of its concentric ridges and in the absence of radial ornament. In an English 

 Great Oolite specimen of F. lajoyei figured by Morris & Lycett (1853, pi. 7, fig. 12) 

 the ribs are more closely spaced in later stages of growth than in early stages, but 

 they are further apart than in the East African specimens. 



Fimbria sp. " B " 



PI. 15, fig. 12 



i960. Corbis lajoyei d'Archiac ; Joubert, pi. 9, fig. ja. 



Material. About four specimens. 



Localities and horizon. Muddo Erri, and Kulong, 2 miles S.W. of Muddo Erri, 

 N.E. Kenya ; Callovian [?-Lower Oxfordian], Muddo Erri Limestones. 



Remarks. A second species of Fimbria found in the Muddo Erri Limestones is 

 the one of which a broken specimen has been figured by Joubert (i960) as Corbis 

 lajoyei. It has relatively distant concentric ridges with intervals in which radial 

 threads are well seen. This species is probably distinct from the true F. lajoyei, 

 but this point cannot be decided definitely owing to the poor state of preservation of 

 the material. Several of the Kenya specimens, like the one represented in Joubert's 

 pi. 9, fig. 76, are internal moulds and quite unidentifiable. 



Fimbria quennelli sp. nov. 

 PL 16, fig. 7 



Specific name. After Mr. A. M. Quennell, formerly Director of the Tanganyika 

 Geological Survey. 



Diagnosis. Large, with the height four-fifths of length (93 mm. in holotype), 

 broadly rounded anteriorly, tapering posteriorly to a low, subtruncate extremity. 

 Limbo moderately prominent, submedian ; postero-dorsal outline almost straight, 

 sloping to meet low subvertical posterior margin in a rounded-off , obtuse angle ; 

 antero-dorsal outline well excavated ; ventral margin asymmetrical, strongly con- 

 vex anteriorly, more weakly convex posteriorly. An obtuse ridge, best seen in later 

 stages of growth, runs from postero-ventral angle of shell towards umbo. Ornament 

 consisting of coarse, rounded concentric ribs separated by much narrower furrows 

 and crossed by weak radial riblets, best seen on anterior half of surface. Ventral 

 margin crenulated internally. 



Holotype and paratype. Holotype, no. LL.16841 and one imperfect paratype. 



