EXPLANATION OF PLATE I.' 



Pape. 

 OnoLKLLA DISCOIDEA _ 42Q5 



Fig. 1. View of a tlorsal valve, enlarged, showing the orbicular form. 



2. View of a ventral valve, showing the truncated beak. Enlarged. 



Ll.NGULEIMS? MINUTA 206 



Fig. 3. View of a ca.st of the shorter valve, enlarged, showing muscular soars. 



4. View of the cast of a long valve enlarged, showing the muscular scars more .spreading 

 thau in the other valve. 



LiNGULEPis M^i;a 20t) 



Fig. 5. View of a supposed ventral valve showing the extended beak. 



6. A larger valve having a shorter beak. This m.ay be a dorsal valve. 



7. Outline showing the relative gibbosity and length of the two valves. 



L1XGI1LKP1.S Ella .23.3 



Fig. 8. View of a dorsal (?) valve showing the truncation of the beak. Enlarged to two 

 diameters. 



OliTIlIS POGONIPEXSIS ijg.^ 



Fig. 9. View of a dorsal valve of rather more than the ordinary size. Enlarged. 



10. A ventral valve of the ordinary size, and of an elongate form, showing the elevation 

 of the beak. 



KUTOltGINA MINUTISSIMA 207 



Fig. 11. View of a dorsal valve, greatly enlarged, showing the peculiar striaj and the faint 

 radiations on the surt:ice. 

 12. A ventral valve having a more elongate form. 



LEPT.ENA MeLITA 



Figs. 13-14. Views of two different individuals, showing variation in the surface-characters. 



STROPnOMENA NeMBA 



Fig. 15. View of the specimen described, showing the general form and surface-strias. 



PORAMBONITES OBSCURUS 234 



Fig. 16. View of the exterior of a ventral valve, showing the lamellfe projecting inward from 

 the beak. 



Maclurea minima 235 



Fig. 17. View of the spire of an intei-nal cast of a specimen. Enlarged. 



18. View of the flat side of the same individual. 



19. Protile view of the specimen, showing the depth of the shell. 



• The liii« drawn by the siile of fl-ures iudicates the natural eiie. ' 



208 



233 



