PLATE XX 



Polyphemopsis lo uisvillae. 



Fig. 16-19. A series of specimen showing variations in size. Page 180 



Macrocheilus carinatus. 



Fig. 20-23. A series of specimen showing variations in size. Page 180 



Trochonema rectilatera. 



Fig. 1, 2. Apertural and dorsal view of a specimen. Page 189 



Trochonema yandellana. 



Fig. 3. Apertural view of a specimen. Page 190 







Calloncma bellatula. 



Fig. 4-7. A series of specimen showing variations in size and orna- 

 mentation. Page 175 



Loxonema hydraulicum. 

 Fig. 8, 9. View of three specimen enclosed in matrix. Page 178 



Cyclonema cancellata. 

 Fig. 10, 11. Dorsal and apertural view of a specimen. Page 187 



Callonema imitator. 

 Fig. 12, 13. Vertical and apertural view of a specimen. Page 176 



Goniatites discoideus. 

 Fig. 14, 15. Basal and profile view of a specimen. Page 194 



