PLATE 65. 



Page 



Fig. 1. Platyceras undulostriatum. 336 



1 a. View of the upper side of the spire. 



1 b. The lower side, showing the narrow groove in the last volution. 



Fig. 2. Platyceras clavatum. 337 



2. A specimen of this species, from which the shell is nearly exfoliated. 



Fig. 3. Platyceras curvirostrum. 338 



8 a. The upper side of the Spire, from wliich the surface is nearly all exfoliated. 

 3 b. The posterior side, showing the form of the aperture. 



Fig. 4 & 7. Platyceras agreste. 338 



7. The lower side of the specimen, showing the aperture. 



4. A specimen having a similar form of the body-volution, but with tlie apex more acute. 

 The shell on the upper part of the volution is marked by abruptly undulating longitudinal 

 striae, and, near the base, the surface becomes roughly cancellated by the two sets of striae. 



Fig. 5. Platyceras elongatum? var. 335 



6 a. A fragment of a specimen, natural size. 

 5 b. An enlargement of the surface strise. 



Fig. 6. Platyceras arcuatum. 336 



6. Lateral view of the specimen, natural size. 



Fig. 8. EUOMPHALUS DISJUNCTUS. 340 



8. The lower side of a weathered specimen of this species. 



