PLATE 49 A. 
Page 
1. Cypricardinia lamellosa. 266 
1 a. A specimen, natural size. 
1 b. The same enlarged to nearly three diameters. 
1 c. Cardinal view of the same enlarged. 
2. Cypricardinia dorsata. 267 
2. The right valve of this species. 
3. Megambonia mytiloidea. 276 
3 a. The right valve of the specimen. 
3 b. Profile view of the same. 
4. Megambonia oyoidea. 276 
4 a. The left valve of the specimen. 
4 b. Profile of the same, looking upon the cardinal line; the beak of the right valve broken off. 
5. Megambonia suborbicularis. 273 
5. A cast of the left valve of this species, 
6. Avicula subequilatera. 281 
fi. The left valve of this species. 
7. Megambonia obscura. 277 
7. The right valve of the specimen. 
8. Megambonia aviculoidea. 274 
8. The left valve of a specimen of this species. 
9. Avicula [?] naviformis. 279 
9 a. A left valve preserving the entire form, with some remains of the shell, showing the 
concentric lamellose markings and the radiating stria. 
9 c. A larger individual in which the radiating stria are scarcely shown. 
9 b. A large individual, in which the shell is better preserved than in the other specimens : 
the umbo is proportionally less elevated, and the continuity of the hinge-line is interrupted 
or obscured by the surrounding stone. The radiating stria are a little too strong in the 
figure. 
