FROM TANGANYIKA AND KENYA 109 



trum. The rostrate specimens closely resemble the Hettangian species Cypricardia 

 triangularis Terquem (1855 : 304, pi. 20, figs. 14, 14a), which may be a Prcnoella. 

 Except for the small size the present species also much resembles Pronoella elongata 

 Cox, from the Aalenian of England, type species of the subgenus Gythemon Casey, but 

 its dentition resembles that of Pronoella s.str. (Casey 1952 : 145, text-fig. 34) rather 

 than that of Gythemon (Casey : 151, text-fig. 47) in the relative strengths of the 

 various hinge-teeth and in the anteriorly pointing direction of the tooth (1). 



Pronoella putealis sp. nov. 

 PL 17, figs. 10, 11 



Diagnosis. Of small-medium size (length of holotype 21 mm.), cuneiform, 

 moderately inequilateral, height two-thirds of length, beaks at anterior three- 

 sevenths of length ; inflation apparently only moderate (the specimens have, how- 

 ever, suffered compression). Umbo obtusely angular, moderately prominent, 

 slightly incurved to prosogyrous beak. Antero-dorsal and postero-dorsal outlines 

 concave, the latter forming an obtuse angle with the low, subvertical posterior mar- 

 gin ; ventral margin of feeble to moderate convexity ; anterior margin broadly 

 convex. No bordered lunule or escutcheon ; a thin, raised keel runs from the beak 

 to the postero-ventral corner. Surface ornamented with fine, regular concentric 

 threads, which are absent from the area dorsal to the keel. Hinge-teeth (seen only 

 in fragments from well washings) as in typical Pronoella, but median cardinals (1) 

 and (2fl) stouter in than P. pindiroensis. 



Holotype and paratypes. Holotype, no. LL.35141 ; two paratypes, including 

 no. LL.35142. There are also several fragments from well sample washings. All 

 ex B.P. Coll. 



Localities and horizon. Lihimaliao creek, at a point near Mbaru creek, 

 Mandawa area, Tanganyika (type-locality) ; Mandawa well no. 6, Tanganyika (depths 

 46-64 feet) : Bajocian (?), Pindiro Shales. 



Remarks. This species is smaller than P. pindiroensis and is also readily distin- 

 guishable by its fine, regular concentric ornament. 



Pronoella kidugalloensis sp. nov. 

 PL 18, figs. la, b 



Diagnosis. Of medium size (length 24-5 mm.), cuneiform, strongly inequilateral, 

 height about three-quarters of length, beaks at anterior sixth of length, inflation 

 moderately strong. Umbo broadly rounded, slightly incurved to the prosogyrous 

 beak, its outline continuous posteriorly with the feebly convex, rather steeply 

 sloping postero-dorsal outline of shell. Posterior margin low, subvertical ; ventral 

 margin with very shallow sinus posterior to middle of its length, and merging anterior- 

 ly in a broad curve with the feebly convex, prosocline anterior margin ; antero- 

 dorsal outline a little excavated. Lunule broad and deep ; escutcheon broad but 



