EXPLANATION OP PLATE 26 



Pig. Iff. Trigonarea sectilis, u. sp. Exterior of right valve. 

 Fig. lb. Trigonarea sectilis, rj. sp. Posterior aspect of the type. 

 Fig. lc. Trigonarea sectilis, n. sp. Anterior dorsal aspect of type. 



Figs, la, lb, lc, type no. 12316, loe. 2144 

 Fig. 2. Ostrea taxidonta, n. sp. Type no. 12317, loc. 2167. 

 Fig. 3. Ostrea erescentiea, n. sp. Type no. 12318, loe. 2144. 

 Fig. 4. Ostrea erescentiea, n. sp. Specimen no. 12319, loc. 2143. 



All figures approximately natural size. 



[438] 



