FROM TANGANYIKA AND KENYA 147 



of whorls, situated at about the lower third of their height, formed by an obtuse 

 angulation bearing large rounded tubercles, above which the whorl outline is feebly 

 concave. Spire whorls ornamented, in addition, with a row of small tubercles 

 bordering the upper suture and with very weak spiral threads which are present on 

 their entire surface except where removed by erosion. Margin of base formed by a 

 narrow, smooth cord continuing the line of the suture ; base ornamented with spiral 

 riblets. Aperture circular (its margin is imperfect). 



Holotype. No. GG. 10263. The only specimen. 



Locality and horizon. Didimtu hill, 2 miles S. of Bur Mayo, N.E. Kenya ; 

 Upper Lias, Toarcian, Didimtu Beds. 



Remarks. This small shell is unquestionably congeneric with Turbo bertheloti 

 d'Orbigny, the type species of Hamusina, but it differs from that species in obvious 

 details of ornament. No species very closely comparable to it is described in the 

 literature. 



Superfamily SUBULITACEA 



Family PSEUDOMELANIIDAE Fischer 1885 



Genus PSEUDOMELANIA Pictet & Campiche 1862 



Pseudomelania aspasia (d'Orbigny) 

 PI. 24, fig. 10 



1850a. Chemnitzia Aspasia d'Orbigny : 298. 



1851. Chemnitzia Aspasia d'Orb. ; d'Orbigny : 49, pi. 242, fig. 4. 



1 85 1. Chemnitzia niortensis d'Orbigny : 48, pi. 242, figs. 1, 2. 



1885. Pseudomelania niortensis (d'Orb.) ; Cossmann : 172, pi. 9, figs. 6, 7. 



Material. One shell (no. GG.10317). Two incomplete internal moulds may also 

 belong to the species. 



Localities and horizons. Shell-bearing specimen from Nchia stream, 2 miles 

 W.N.W. of Mandera, Tanganyika ; internal moulds from Lonji stream, E.N.E. of 

 Nandenga, Tanganyika ; Callovian. 



Remarks. The shell-bearing specimen agrees so closely with the figures of P. 

 aspasia published by d'Orbigny and by Cossmann that I see no reason to qualify its 

 specific determination. The species occurs typically in the Bathonian of France. 

 In P. caecilia (d'Orbigny) (1851 : 64, pi. 248, fig. 2 ; de Loriol 1874 : 331, pi. 8, 

 figs. i«, b), from the Lower Kimmeridgian of France, and P. laufonensis Thurmann 

 & Etallon (1861 : 88, pi. 6, fig. 27), a Swiss species of about the same age, the spire 

 angle is about the same but the whorls are quite flat. 



On the internal moulds now recorded there is a tendency for a spiral groove to be 

 developed low on the side of the whorl, just above the lower suture. As it is dis- 

 continuous it does not appear to represent a spiral fold on the interior of the whorls 

 and it may have arisen by deformation of the internal mould after the shell had 

 disappeared in solution. 



