44 JURASSIC BIVALVIA AND GASTROPODA 



hinge-margin is about three-fifths of that of the shell. When not broken away, an 

 acute anterior auricle extends well beyond the umbo, which projects only slightly 

 above the hinge-margin. The anterior and ventral margins form a strongly convex, 

 uninterrupted curve. The body of the shell, which varies considerably in breadth 

 and obliquity, is evenly and moderately inflated, its level descending gradually to the 

 anterior margin and to the posterior wing. The growth-lines show that the posterior 

 wing, which is obtusely triangular in general shape, was acutely pointed at its 

 extremity in earlier growth-stages. In the material examined some shell fragments 

 show traces of hinge-teeth, but the complete dentition is not displayed. 



Remarks. This species was based on several broken specimens from Jebel 

 Aroussieh, Sinai. Douville queried their age as Callovian, but a specimen collected 

 more recently is from beds which are undoubtedly Bathonian in age. Douville 's 

 figures indicate a range of variation similar to that shown by the specimens now 

 described, and justify the inclusion of all of these in the same species. The present 

 specimens, however, lack the radial sulcus of the body of the shell observable in 

 specimens from Sinai. The less expanded specimens of the species rather resemble 

 Gervillella ovata (Morris & Lycett), an English Bathonian form, differing mainly in 

 the presence of the pointed anterior auricle. G. iraonensis (Newton), Bathonian of 

 Madagascar, is a more gibbose shell with a broad sinus of the anterior margin. 



Gervillella siliqua (Eudes-Deslongchamps) 

 PL 4, fig. 10 



1824. Gevvillia siliqua Eudes-Deslongchamps : 128, pi. 4. 



1940. Gervillella siliqua (Eudes-Deslongchamps) ; Cox : 112, pi. 7, figs. 12-14. 



Material. One specimen (no. L. 92032). 



Locality and horizon. Tifo, 14 miles N. of Wergudud, N.E. Kenya ; Oxfordian, 

 Golberobe Beds. 



Remarks. The specimen now recorded, which is about 45 mm. long, closely 

 resembles one from the Oxfordian of Cutch, India, represented in fig. 13 of the work 

 cited above. To the synonyms of G. siliqua there given should probably be added 

 Gervillia mayeri Moesch (1867 : 308, pi. 5, figs. 10a, b). 



Gervillella aviculoides (J. Sowerby) 



1814a. Perna aviculoides J. Sowerby : 147, pi. 66, figs. 1-4. 



1836. Gervillia telragona Roemer : 85, pi. 4, fig. n. 



1875. Gervillia telragona Roemer ; de Loriol : 165, pi. 19, figs. 3-5. 



1933a. Gervillia aviculoides (J. Sowerby) ; Arkell : 203, pi. 26, figs. 1-5. 



IQ 33- Gervilleia {Gervillella) sp., aviculoides-Gruppe ; Dietrich : 60. 



Material. Several imperfect specimens. 



Localities and horizons, i mile N.W. of Tendaguru hill and scarp at Kindope, 

 N.N.W. of Tendaguru, Tanganyika ; Upper Kimmeridgian, Nerinella Bed. Tin- 



