EXPLANATION OF PLATE III. 



Page. 



Strophodonta Canace 246 



Fig. 1. View of a very yoiinnr iudividnal. 



2-3. Dorsal and ventral views of an older individual, presenting the features of the 

 species. 



RH YNCHONELLA EmMONSI 247 



Figs. 4-8. Dorsal, ventral, profile, front, and cardinal views of a full-grown and well-fonued 

 specimen. 



LUSl:LICAKDinM FRAGOSUM 249 



Fig. 9. View of a short form, enlarged, showing strong undulations, and retaining the ante- 

 rior flange, of large size. 



10. An elongated form, enlarged, showing a narrower anterior projection. 



11. A right valve of medium proportions, showing a strong anterior flange. 



Nlcuutes triangclus 248 



Fig. 12. View of a left valve, showing the surface-characters. 



13. View of the same individual after having the shell removed from all but the hinge- 

 margin, and showing the impression of the clavicle very faintly. 



Paracyclas peroccidens ; 248 



Fig. 14. View of a specimen, preserving a part of the external shell. 



15-17. Right, left, and profile views of a cast, showing the muscular imprints and pallial 

 line. 



RuiLEROPiiON Neleus 250 



Fig. 18. View of a fragment, showing the callus of the inner lip and a small part preserving 

 the external ornamentation. 



19. Front view of an internal cast, showing the form of the lip and dorsal slit. 



20. Profile view of the same individual, showing the axial cavity filled with the thick- 



ened shell-substance. 



