PLATE 35. 
Fig. 1. 197. 1. EpMoNnDIA VENTRICOSA. (Pag. 155.) 
1 a. Right valve of a large and perfect specimen. 1 6. Anterior extremity of the same. 1c. Dorsal view. 
1d. Left valve of a smaller individual. 
1 e. Left valve of a specimen which has been compressed vertically. 1 f. Dorsal view of the same. 
Fig. 2. 199. 3. EpMonpia? sUBANGULATA. (Pag. 156.) 
2a. Lett valve of this species, 2b. Dorsal view of a single valve. 
Fig 3. 198. 2. EpMoNnDIA SUBTRUNCATA. (Pag. 156.) 
3 a, b. Casts of this species, in the crystalline limestone at Watertown. 
3c. A cast, showing strong imbricating ridges towards the base. 
Fig. 4. 200. 1. MoproLopsis myTILoIDEs. (Pag. 157.) 
4 a. Right valve of a specimen, showing the muscular impression. 4 b. Dorsal view. 
Fig. 6. 201. 2. MopioLopsis PARALLELA. (Pag. 158.) 
Fig. 6. 202. 3. Mopioopsis FaBa. (Pag. 158.) 
6 a. A large and characteristic form, the muscular impression visible‘at the anterior extremity. 
6 6. A smeller specimen, less regularly rounded. 
6 c, A specimen having a more oblique form, with the anterior lobe more compressed and extended. 
6d. A young specimen, having the umbones and sinus nearly central. 
Fig. 7. 203. 4. MopioLopsis NasuTus. (Pag. 159.) 
Vag. 3.) <* 204. 5. Mopiouopsis arcuatus- (Pag. 159.) 
Fig. 9. 205. 6. MobioLopsis sUBSPATULATUS. (Pag. 159.) 
9 a. View of the right valve of this species. 9 6. Dorsal view of the same. 
Fig. 10. 206. 7. MopioLopsis Latus. (Pag. 160.) 
10 a, b. The left valves of two specimens, showing a slight variation in form. 
Fig. 11. 207. 8. MopioLorsis cARINATUS. (Pag. 160.) 
11 a. A large specimen, with prominent umbones. 
11 6. A smaller specimen, showing the true form of the shell more distinctly than the last. 
il ce. A smaller specimen, in which the posterior margin is less oblique. 
