PLATE 38. 
Fig. 1. 74. ‘7. PLEUROTOMARIA UMBILICATA. (Pag. 175.) 
1 a. Back of the shell, showing an elevated spire. 1b. Front view, showing the aperture. 1c. Base. 
1d. Top of the spire of a larger specimen. 1 e. Front view, showing a depressed spire. 1f. Base. 
1 g- Specimen from Mineral Point, showing a greater elevation of the spire. 
Fig. 2. 226. 14. PLEUROTOMARIA INDENTA. (Pag. 176.) 
Fig. 3. 227. 15. PLEUROTOMARIA AMBIGUA. (Pag. 176.) 
3 a. View of the back of the spire. 3 b. Front of the same, showing the aperture. 
Fig. 4. 228. 16. PLEUROTOMARIA PERCARINATA. (Pag. 177.) 
Fig. 5 229. 6. MuRcHIsonia BICINCTA. (Pag. 177.) 
5 a. Front view of a nearly perfect specimen, showing the form of the aperture. 5 b. Back view. 
5 e. Front view of a specimen with the last volution broken off behind the aperture. 
5 d. View of an imperfect specimen, showing the direction of the striz. 5 e. Enlarged view of the same. 
5 f. A smooth cast from crystalline limestone, scarcely preserving the upper carination in an obscure angle. 
5 g. A large imperfect specimen, still preserving the striz upon the surface. 
5A. A portion of the same enlarged. 
Fig. 6. 230. 7. MuRcHISONIA TRICARINATA. (Pag. 178.) 
6 a. View of the back of the shell. 
6 b. Front view, showing the aperture, which is imperfect on the outer side. 
6c. A fragment apparently belonging to the same species ; but the striz are much better preserved, and the 
carine sharply projecting. 
Fig. 7. 231. 8. MurcHIsonia PERANGULATA. (Pag. 179.) 
7 a. Back of the spire, showing six volutions. 7b. A portion of the surface, with the strie enlarged. 
Fig. 8. 232. 9. MuRcHISoNIA UNIANGULATA. (Pag. 179.) 
