PLATE 59. 
Fig. 1-4. 
Platyceras unguiforme. 
1 a, b. & 2. Views of young individuals of this species. 
3 a. Profile view from the dorsal side, showing the spire and the broad flat plications. 
3 b. View of the upper side of another specimen, with more numerous plications. 
4 a, var. multicarinatum. View of the lower side of a specimen which has numerous narrow 
plications. 
4 b, c. Views of the upper sides of similar specimens. 
Fig. 5 a - i & 6 c. Platyceras dilatatum. 822 
5 a, b. Young specimens of this species. 
5 c. A larger specimen, showing a shallow sinus on the back and the commencement of small 
plications on the right side. 
5 d . A larger specimen where the plications are more fully developed. 
5 e. Dorsal view of a similar specimen in which the plications are more developed, and the 
obtuse carina extending from the apex is more defined, and ending in a broad extension 
in front (which is broken off in the specimen figured ). 
5/. View of the aperture of the same specimen, showing the incipient plications upon the 
left side of the aperture. 
5 g. A specimen in which the spiral carina is more strongly developed, and is marked by a 
deep sinuosity in the peristome. 
5 h. An enlargement of the surface, showing the bending of the striae as they cross the carina. 
5 i. An enlargement of the surface of a young specimen, where the longitudinal striae are 
more conspicuous. 
6 c. This specimen is probably one of the same species, which is less expanded towards the 
aperture, and has one more volution at the apex than the preceding figures. 
Fig. 6 a , b . Platyceras tenuiliratum. 817 
6 a, b. The specimen may be a compressed form of this species. 
Fig. 6 d - g , & 7 a . Platyceras gibbosum. 328 
6 d. View of the aperture of a large specimen of this species. 
6 e. A similar specimen, with less strongly plicated margins and a smaller spire. 
G/. The upper side of the spire of fig. 6 e. The specimen is not quite symmetrical in its 
convexity. 
6 g. The upper side of the spire of the specimen fig. 6 d. 
7 a. The lower side of a smaller specimen, showing strong plications. 
Fig. 7 b . Platyceras sulcoplicatum. 324 
7 b. The figure represents the specimen lying with the aperture downward. 
Fig. 8. Platyceras perplicatum. 325 
8. Anterior view of the specimen. 
Fig. 9. Platyceras retrorsum. 320 
9 a, b. A specimen which is probably of this species : it is broken at the apex, and somewhat 
otherwise distorted. 
Fig. 10. 
Platyceras plicatile. 
325 
10 a. View of the upper side of the shell. 
10 b. View of the aperture. 
