FROM TANGANYIKA AND KENYA 87 



species Astarte daphne de Loriol (1891 : 244, pi. 26, figs. 25-27), Upper Oxfordian of 

 Switzerland, is comparable in size and shape, but its concentric ribs are more closely 

 spaced. 



Astarte muelleri Dacque 



1900. Astarte sp ; Miiller : 534, pi. 17, fig. 7. 

 1910. Astarte mulleri Dacque : 31, pi. 4, fig. 5. 

 19376. Astarte mulleri Dacque ; Cox : 202. 



Material. One specimen (no. L.54117). 



Localities and horizons. 2 miles E. of Magindu Station, Central Railway, 

 Tanganyika ; Callovian. Miiller's original specimen came from a locality 1-5 km. 

 W. of the Mahokondo stream, 24-5 km. N.W. of Kiswere, where the beds are now 

 thought to be Callovian in age. 



Astarte aitkeni sp. nov. 

 PL 12, figs. 9a, b, c 



Specific name. After Dr. W. G. Aitken, lately Director of the Geological Survey 

 of Nyasaland, collector of the holotype. 



Diagnosis. Rather small (length of holotype 12 mm.), trigonally orbicular, 

 slightly higher than long, compressed, early growth-stages flattened. Umbones just 

 anterior to median, obtusely angular. Postero-dorsal outline strongly convex, steep, 

 meeting almost semicircular ventral margin in an ill-defined angle ; anterior outline 

 very feebly convex, steep. Escutcheon narrow, no lunule. Surface, up to mid- 

 growth, bearing obtusely angular ridges, widely separated except near umbo, the 

 last two 3 mm. apart ; later growth-stages bearing only rather fine concentric 

 threads. 



Holotype. No. LL.35189. The only specimen. 



Locality and horizon. Nchia stream, 2 miles W.N. W. of Mandawa, Tangan- 

 yika ; Callovian. 



Remarks. This species differs from A. huralensis Stefanini, recorded below (p. 89), 

 in its taller form, in the wider spacing of its obtuse concentric ridges, and in the ab- 

 sence of such ridges in later stages of growth. 



Astarte unilateralis J. de C. Sowerby 

 PL 14, figs. 2, 3 



18406. Astarte unilateralis J. de C. Sowerby : 327, pi. 21, fig. 14. 



1863. Astarte hermanni Oppel : 272. 



1865. Astarte unilateralis Sow. ; Salter in Strachey : 97, pi. 23, fig. 10. 



1913. Astarte hermanni Oppel ; Holdhaus : 440, pi. 99, figs. 7-1 1, 14. 



Material. Two specimens (nos. LL.35118-19), ex B.P. Coll. 



Locality and horizon. Lonji creek, W. of Mandawa, Tanganyika ; Callovian? 



