FROM TANGANYIKA AND KENYA 149 



East African specimen from those from England, where, however, the species seems 

 to be confined to the Cornbrash (Upper Bathonian-Callovian). The original length 

 of this specimen was about 120 mm., but it now lacks the apical whorls. 



In the well-known species P. heddingtonensis (J. Sowerby), of the Upper Oxfordian 

 and Lower Kimmeridgian of Europe, the size and proportions of the shell are much 

 the same as in the specimen now recorded, and in some specimens there is a slight 

 spiral swelling of the whorl face in the same position as the upper carina of P. vittata. 

 The outer face of the whorl is, however, convex and there is no carina at the per- 

 iphery of the base. Hudleston (1882 : 245) commented on the doubtful value of 

 the specific distinctions drawn between a number of Jurassic " Chemnitzias ", 

 but thought that the slight differences noted might depend upon the geological 

 horizon. It is evident from the occurrence now recorded that the differences 

 between P. vittata and P. heddingtonensis have no stratigraphical significance. 



Of other Upper Jurassic species of the group now described, P. sulcata (Zieten) 

 (Brosamlen 1909 : 283, pi. 21, fig. 15), from the Kimmeridgian of Nattheim, southern 

 Germany, and a series of forms from France (P. athleta, P. pollux, P. columna, P. 

 domoisii, etc.) illustrated by d'Orbigny (1851, pis. 245-248), all, like P. heddington- 

 ensis, differ from P. vittata in lacking the lower of the two carinae on the last whorl. 



Subgenus OONIA Gemmellaro 1878 



Pseudomelania (Oonia) kidugalloensis sp. nov. 

 PL 26, figs. 4a, b, c 



Diagnosis. Shell of medium size for the genus (height of holotype 10-4 mm.), 

 phasianelliform, height of aperture about three-sevenths of that of shell ; spire 

 angle about 40°. Protoconch unknown complete. Spire whorls strongly convex, 

 about twice as broad as high, abutting simply at the sutures ; last whorl evenly 

 convex at periphery. Base also evenly convex in outline, not much extended, 

 without umbilicus. Aperture obliquely oval, its height nearly twice its breadth. 

 Columellar lip short, apparently joining basal margin of aperture in an even curve. 

 Outer lip almost orthocline ; details of parietal region not well seen. Growth-lines 

 obscure. 



Holotype. No. GG. 10280. The only specimen. 



Locality and horizon. 2| miles N.N. W. of Kidugallo, Tanganyika ; Bajocian. 



Remarks. This species seems closely comparable to the English Bajocian species 

 " Phasianella " latiuscula Morris & Lycett, as figured by Hudleston (1891 : 251, pi. 

 19, figs. 10a, b), but its spire occupies a relatively greater proportion of the height of 

 the shell than in that species and it is much smaller. The English species is included 

 in Pseudomelania {Oonia) by Cox & Arkell (1950 : 97). 



