[66 JIRASSIC BIVALVIA AND GASTROPODA 



Mbinga. Just W. of Mabokweni, 4 miles N.W. of Tanga, Tanganyika (type-locality) ; 

 Kimmeridgian. 



Remarks. The specimens now recorded come from two rather widely separated 

 horizons (Callovian and Kimmeridgian), but the material available does not justify 

 their reference to more than one species. The sutural ledge is a little broader in the 

 Kimmeridgian specimen serving as holotype than in the Callovian specimens, but 

 the difference is no greater than is commonly found in specimens of the same species 

 of Ampullospira. 



The sutural ledge suggests comparison with several forms found in the Bathonian 

 of Europe, for example, A. gradifera (Piette) (Cossmann 1885 : 138, pi. 16, figs. 15, 

 16), but its lower spire distinguishes the present species from any of these forms. In 

 A. crithea (d'Orbigny) (1852 : 200, pi. 292, figs. 5, 6), Lower Oxfordian of France, the 

 shell is less globose and the sutural ledge narrower and more excavated. 



A species of the genus Globularia, " Natica " pelops d'Orbigny (1852 : 188, pi. 288, 

 figs. 16, 17), from the Upper Lias of France, may be mentioned particularly as 

 closely resembling the present form in the general shape of the shell and in size, but 

 it lacks a sutural ledge. 



Genus GLOBULARIA Swainson 1840 



Globularia hemisphaerica (Roemer) 

 PL 28, fig. 9 



1836. Nerita hemisphaerica Roemer : 156, pi. 10, figs, ya, b. 



1852. Natica hemisphaerica d'Orb. ; d'Orbigny : 204, pi. 294, rigs, i, 2. 



1861. Natica hemisphaerica d'Orb. ; Thurmann & Etallon : 118, pi. 10, fig. 75. 



1868. Natica hemispherica (Roemer) ; de Loriol : 43, pi. 3, figs. 3, 4. 



1872. Natica hemispherica (Roemer) ; de Loriol : 118, pi. 8, figs. 4-6. 



1881. Natica hemispherica (Roemer) ; de Loriol : 33, pi. 8, fig. 7. 



1887. Natica hemisphaerica (Roemer) ; de Loriol : 152, pi. 16, fig. 7. 



1905. Natica cf. amata d'Orb. ; Krumbeck : 127, pi. 13, figs, ga, b. 



1909. Natica hemisphaerica (Roemer) ; Brosamlen : 269, pi. 20, fig. 36. 



i960. Globularia hemisphaerica (Roemer) ; Joubert, pi. 12, figs. 4a, b. 



Material. Four specimens (nos. G. 76374, G. 76384-86). 



Localities and horizon. Melka Dakacha, N.E. Kenya, and 3 miles to the N.E. ; 

 also N. of Figfirya, northern Raiya hills, N.E. Kenya. All Upper Kimmeridgian, 

 Dakacha Limestones. 



Remarks. This species, with its very low, obtusely rounded spire, its large last 

 whorl, and its wide, obliquely extended aperture, is easily recognized. In Europe 

 its range extends throughout the Kimmeridgian and probably into the Portlandian. 



Globularia phasianelloides (d'Orbigny) 

 PL 29, figs, ia, b 



1852. Natica phasianelloides d'Orbigny : 212, pi. 297, fig. 6. 



1872. Natica phasianelloides d'Orbigny ; de Loriol : 115, pi. 7, figs. 19, 19a. 



