PLATE 32. 
Fig. 1. 155. 2. ORtuHis TESTUDINARIA. (Pag. 117.) 
1 a. Ventral valve. 1 b. Profile view of the shell. 1 ¢. Dorsal valve. 1 d. Cardinal view of shell. 
1 e. A smaller specimen. 1 f. Interior of the dorsal valve. 1 g. Interior of the ventral valve. 
1A. Cast of the dorsal valve. 1%, k,l. The same species from the Blue limestone of Ohio. 
Fig. 2. 156. 3. Orruis supzQuata. (Pag. 118.) 
2a. Ventral valve. 2b. Dorsal valve. 2c. Profile view. 2 d. Cardinal view. 
2e, f. Figures of a smaller specimen; the ventral valve being less convex than in the older specimen. 
Fig. 3. 157. 4. Onrrtuis BELLARUGOSA. (Pag. 118.) 
3 a. Ventral valve. 3 6. Dorsal valve. 3c. Profile view. 3 d. Cardinal view. 
3 e. An enlarged portion of the surface, showing the imbricating squamose lamelle. 
Fig. 4. 158. 5. ORTHIS DISPARILIS. (Pag. 119.) 
4a. Ventral valve. 4 6. Dorsal valve. 4c. Profile view. 4 d, Cardinal area and foramen. 
Fig. 5. 159. 6. OnRrHis PERVETA. (Pag. 120.) 
5 a. Ventral valve. 5b. Cardinal view. 5c. Profile view. 5 d. Cardinal view magnified. 
Fig. 6. 160. 7. ORrrHis ®QUIVALVIS. (Pag. 120.) 
6 a. Ventral valve. 6 b. Dorsal valve. 6 ec. Cardinal view, showing the equality of the valves. 
Pig., 7. 161. 8. Orruis Fissicosta. (Pag. 121.) 
7 a. Ventral valve. 7b. Profile view, showing the projecting beak of the dorsal valve. 
Fig. 8. 162. 9. OnrTHIS TRICENARIA. (Pag. 121.) 
8 a. Ventral valve and area. 8 b. Interior of the dorsal valve. 8c. Exterior of the dorsal valve. 
8 d. Interior of the ventral valve. 8 e. Profile view of a perfect specimen. 
Fig.9: 163. 10. Onrtnis PLICATELLA. (Pag. 122.) 
9 a, b, ce. Ventral valves. 9 d. Profile view of the last. 9 e. Cardinal view of the same. 
9 f. Ventral valve of a large specimen. 9 g. Profile view of the same. 
Fig. 10. 164. 11. Onrtnis PEcTINELLA. (Pag. 123.) 
10. A small individual. 10 a. Ventral or convex valve. 10 6. Dorsal valve of the same specimen. 
10 c. Cardinal view of another specimen. 10 d. Ventral valve. 10 e. Interior of the ventral valve. 
Bigs 11s 165. 12. Orruis PECTINELLA, var. SEMIOVALIS. (Pag. 124.) 
11. A large specimen, somewhat imperfect. 11 a, b. Dorsal and ventral valve of a smaller individual. 
Bigs wl2s + 166. 13. Orruis tnscuLpTa. (Pag. 125.) 
12 a. Dorsal valve, the beak imperfect. 12 b. Interior of the dorsal valve. t2 ¢. Dorsal area. 
Fig. 13. 167. 14. Orruis picHoroma. (Pag. 125.) 
13 a, Ventral valve, showing the projecting dorsal beak. 13 &. Profile view of the same. 
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