PLATE 41. 



Fig. 1. 247. 2. Cyrtolites trentonensis. (Pag- 189.) 



1 a. Lower surface of an imperfect specimen. 1 4. A portion of the surface striae enlarged. 



1 c. Section of the shell below the aperture ; the upper surface of the figure being the dorsal margin. 



Fig. 2. 250. 1. Cyrtocekas lamellosdm. (Pag- 193.) 



2 a. Lateral view of the fragment. 2 h. Dorsal view of the same. 2 c. Magnified portion of the surface. 



Fig. 3. 248. 3. Cyrtolites filosttm. (Pag. 190.) 



3 a. Lateral view of the specimen imbedded in stone, the apex being concealed. 



3 b. View of the dorsal side of a small portion of the shell, showing the arched stria?. 



Fig. 4, 5. 251. 2. Cyrtoceras annulatum. (Pag. 194.) 



4 a. A large fragment (a cast), retaining the annulations. 



4 4. A smaller fragment, retaining the shell and transverse striae. ~"' 



4 c. Section of the last, showing the siphuncle. 



i d. A portion of the surface magnified. r . 



5. A fragment of the same species, nearer the aperture. 



Fig. 6, 7. 257. 1. Omcoceras constrictum. (Pag- 197.) 



6 a. View of the ventral side of an imperfect specimen. 



G 4. Lateral view of the same, showing the sudden contraction below the outer chamber : aperture imperfect. 



6 c. Section of the lower extremity, showing the small dorsal siphuncle. 



6 d. A smaller specimen, of the same form as the last. 



6 e. A shorter and more ventricose specimen. (The transverse lines on the npper half of the figure, indicating 



septa, are incorrect.) 

 iif. The apicial extremity of the fossil. 

 1 a, c. Dorsal and lateral views of a fragment, showing the direction of the septa. 



7 4, d. Sections of different specimens, showing the position of the siphuncle, and the narrowing of the dorsal 



side of the sliell. 



