PLATE VI. 



Page. 

 SCOLIOSTOMA AMERICANA 195 



Figs. 1, la. Two views of a specimen showing the aperture with the coluinellar lip broken 



away. Natural size. 

 16, c, d. Three shells showing the inturning and expansion of the coluraellar lip. 



Natural size. 

 1 e. View looking down on the apex of the spire. Natural size. 



PLATYCEBAS UNDULATUM 184 



Figa. 2, 2a. Dorsal and side views. Natural size. 



EUOMPHALUS (P.) LAXUS 186 



Fig. 3. View of upper side, enlarged to two diameters. 



PLATYCERAS THETIFORME 184 



Figs. 4, 4 a, b. Posterior, dorsal, and side views of the cast. Natural size. 



PLATYCERAS NODOSUM 183 



Figs. 5, 5 a, 6. Posterior, dorsal, and side views of the cast of a strongly-marked specimen. 



Natural size. 



ECCULIOMPHALUS DEVONICUS 187 



Figs. 6, 6 a. Dorsal and ventral views of an adult shell. Natural size. 



LOXONEMA APPROXIMATUM 191 



Fig. 7. A specimen with the apex imperfect. Natural size. 



HYOUTHES, sp. t 199 



Figs. 8, 80. Two views of the only specimen obtained. Natural size. 



COLEOLUS L^VIS 199 



Fig. 9. A fragment of shale with numerous tubes lying upon it, enlarged to two diameters. 



