PLATE 35. 



Fig. 1, 197. 1. Edmondia ventricosa. (P«ig> 166.) 



1 o. Right valve of a large and perfect specimen. 1 b. Anterior extremity of the lame. 1 e. Dorsal view. 

 1 d. Left valve uf a smaller individual. 



1 e. Left valve of a specimen which has been compressed vertically. 1/. Dorsal view of the same. 



Fig. 2. 199. 3. Eduondia? subamoulata. (Pb£- 166.) 



2 a. Left valve of this species. 2 6. Dorsal view of a single valve. 



Fig 3. 198. 2. Edmondia subteuncata. (Pag. 1.56.) 



3 a, 6. Casts of this species, in the crystalline limestone at Watertown. 

 3 c A cast, showing strong imbricating ridges towards the base. 



Fig. 4. 200. 1. MoDioLOPSis mytiloides. (Pag. 157.) 



4 a. Eight valve of a specimen, showing the muscular impression. 4 b. Dorsal view. 



Fig. 6. 201. 2. MoDiDLOFSis parallela. (Pag. 168.) 



Fig. 6. 202. 3. MoDioLOPsis faba. ( Pag. 158.) 



6 a. A large and characteristic form, the muscular impression visible'at the anterior extremity. 

 6 i. A smaller specimen, less regularly rounded. 



6 e. A specimen having a more oblique form, with the anterior lobe more compressed and extended. 

 6 d. A young specimen, having the umbones and sinus nearly central. 



Fig. 7. 203. 4. MoDioLOPSis nasutus. (Pag- 159.) 



Fig. 8. 204. 5. MoDioLOPSis arcuatus. ( Pag. 159.) 



Fig. 9. 205. 6. MoDioLOPsis subspatulatus. (P<ig. 159.) 



9 a. View of the right valve of this species. 9 b. Dorsal view of the same. 



Fig. 10. 206. 7. MODIOLOPSIS latus. (Pag- 160.) 



lu a, b. The left valve* of two specimens, showing a slight variation in form. 



Pig. 11. 207. 8. MoDioLOPsis carinatus. (Pag- 160.) 



11 a. A large specimen, with prominent umbones. 



11 b. A smaller specimen, showing the true form of the shell more distinctly than the last. 

 1 1 e. A smaller specimen, in which the posterior margin is less oblique. 



