PLATE 35. 
Fig. 1. 197. 1. Edmondia ventricosa. (Pag. 155.) 
1 a. Right valve of a large and perfect specimen. 1 b. Anterior extremity of the same. 1 c. Dorsal view. 
1 d. Left valve of 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. Edmondia? subangulata. (Pag. 156.) 
2 a. Left valve of this species. 2 b. Dorsal view of a single valve. 
Fig 3. 198. 2. Edmondia subtruncata. (Pag. 156.) 
3 a, b. 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. 
Right valve of a specimen, showing the muscular impression. 
4 b. Dorsal view. 
Fig. 
5. 
201. 
2. 
Modiolopsis parallela. 
(Pag. 158.) 
Fig. 
6. 
202. 
3. 
Modiolopsis faba. 
(Pag. 158.) 
6 a. A large and characteristic form, the muscular impression visible'at the anterior extremity. 
6 4. A smaller specimen, less regularly rounded. 
6 c. 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. 
(Pag. 159.) 
9 a. 
View of the right valve of this 
species. 9 b. Dorsal view of the same. 
Fig. 10. 
206. 
7. 
Modiolopsis laths. 
(Pag. 160.) 
10 a, b. The left valves of two specimens, showing a slight variation in form. 
Fig. 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. 
11 c. A smaller specimen, in which the posterior margin is less oblique. 
