PLATE ii 



Figs. la, b. Gryphaea hennigi Dietrich. Upper Oxfordian. Hill opposite Kingura 

 village, N. of Wami river, Bagamoyo hinterland, Tanganyika. LL. 16848, x 1 . P- 73 



Figs. 2a, fe. Trigonia costa ta Parkinson. Bajocian. Magole, 5 miles N.W. of Kidugallo, 

 Tanganyika. LL. 35104 : a, x 1 ; b, x 2 . . . . . . . P- 74 



Figs. 3a, b, c. Trigonia kidugalloensis sp. nov. Bajocian. \\ miles N.N.W. of 

 Kidugallo, Tanganyika. Holotype, LL. 35105 : a, b, side and dorsal views, x 1 ; 

 c, side view, x 2 . . . . . . . . . . . p. 75 



Figs. 4a, b, c. Trigonia kenti sp. nov. Bajocian. 6 miles N.W. of Kidugallo, Tangan- 

 yika. Holotype, LL.35107 : a, b, side and dorsal views, X 1 ; c, side view, x 2 . P- 75 



Fig. 5. Exogyra nana (J. Sowerby). Oxfordian, Rahmu Shales. i\ miles S.W. of 

 Rahmu, N.E. Kenya. L. 83889, x 1 . . . . . . . . . p. 73 



Figs. 6a, b. Same species, horizon and locality. L. 83891, x 1 . . . P- 73 



Fig. 7. Trigonia cf. brevicostata Kitchin. Bathonian [? or Callovian], Asaharbito 

 Beds. 1 mile N. of Asaharbito, N.E. Kenya. LL.11380, x 1 . . . . p. 76 



Fig. 8. Trigonia elongata J. de C. Sowerby. Callovian ? i£ miles W. of Mandawa, 

 Tanganyika. LL. 35109, x 1 . . . . . . . . . p. 76 



Fig. 9. Trigonia dainellii Venzo. Uppermost Jurassic or basal Cretaceous, Danissa 

 Beds. W. slope of hill £ mile E. of Hafura, N.E. Kenya. L. 92270, x 1 . . . P- 77 



Fig. 10. Trigonia (Frenguelliella) tealei Cox. Callovian. S. of Tarawanda, 11 miles 

 S.E. of Lugoba, Tanganyika. Holotype, L. 541 13, x 1 . . . . . p. 78 



Figs. 11a, b. Trigonia migeodi sp. nov. Upper Kimmeridgian, Nerinella Bed. 1 mile 

 N.W. of Tendaguru, Tanganyika. Holotype, L. 51 193 : a, x 1 ; b, x 2-4 . . p. 77 



