FROM TANGANYIKA AND KENYA 127 



which are closely arranged on the middle of the shell, the most anterior one standing 

 out as a sharp keel. Although its posterior end is broken away, the specimen now 

 recorded seems to be a very typical example of the species. The specimens from 

 Somaliland figured as P. protei by Dacque (1905 : 140, pi. 15, figs. 1-3) and one from 

 Rukesa, N. Kenya, considered by Weir (1929 : 33, pi. 3, fig. 10) to be a young indi- 

 vidual of the species, were wrongly identified. 



Pholadomya hemicardia Roemer 

 PI. 20, fig. 5 



1836. Pholadomya hemicardia Roemer : 131, pi. 9, fig. 18. 



1874. Pholadomya hemicardia Roemer ; Moesch : 58, pi. 23, figs. 1-6 ; pi. 24, fig. 11. 



1935a. Pholadomya hemicardia Roemer ; Arkell : 336, pi. 46, figs. 5-7. 



i960. Pholadomya hemicardia Roemer ; Joubert, pi. 11, figs. 5a, b. 



Material. Two specimens (nos. L. 92186, LL. 35156). 



Localities and horizons. Mandawa-Lonji creek traverse, Mandawa area, Tan- 

 ganyika ; Upper Oxfordian. Hegalu hills, 2 miles N. of Finno, N.E. Kenya ; 

 Upper Kimmeridgian, Dakacha Limestones. 



Remarks. The more complete specimen is 33 mm. long, with the posterior end 

 of the shell rather angular and situated above mid-height. The ornament consists 

 of weak, irregular concentric undulations crossed by weak radial riblets, which are 

 scarcely perceptible on the posterior part of the surface. The specimens appear to 

 fall within the range of variation of P. hemicardia, which in Europe occurs in the 

 Oxfordian and Kimmeridgian. 



Genus HOMOMYA Agassiz 1843 

 Homomya inornata (J. de C. Sowerby) 



18406. Pholadomya? inornata J. de C. Sowerby : 327, pi. 21, fig. 8. 



1874. Pholadomya inornata Sowerby ; Moesch : 53. 



1907a. Pholadomya inornata Sowerby ; Cossmann : 134, pi. 1, fig. 17. 



1912. Pholadomya inornata Sowerby ; Lissajous : 92, pi. 11, fig. 21. 



1921. Pholadomya inornata Sowerby ; de la Bouillerie : 35, pi. 4, fig. 10. 



1924. Pholadomya (Flabellomya) ovulum Agassiz ; Cossmann : 53, pi. 7, figs. 3- 



Material. One specimen (no. L. 92154). 



Locality and horizon. 3! miles W. of Melka Biini, N.E. Kenya. Callovian, 

 Rukesa Shales. 



Remarks. This species, which is ornamented with concentric ribs undulating 

 slightly in places and may also bear a few faint radial threads (actually just visible 

 on Sowerby 's holotype), was described originally from the Callovian of India. It 

 has been recorded by authors cited above from the Callovian of France. Cossmann 

 (1924), however, has suggested that the French specimens would be more correctly 

 identified as Pholadomya ovulum Agassiz (= P. ovalis (J. Sowerby)). This view is 



