PLATE 54 a. 
Page 
Figs. 1-10. Rhync honell a (Stenocisma) prolific a. 343 
1-3. Dorsal views, showing gradation in size and form. 
4-6. Ventral, profile and front views of specimen, fig. 3. 
7. Front view of a small specimen, in which the mesial elevation is not distinctly marked. 
8- 10. Dorsal, ventral and profile views of an unusually large specimen. 
Figs. 11-20. Rhynchonella (Stenocisma) dotis.. 344 
11 -14. Dorsal, ventral, profile and front views of an individual of medium size, having sharply 
angular plications. 
15 -18. Dorsal, ventral, profile and front views of a broad form where the plications are 
rounded. 
19, 20. Dorsal and front views of a more elongate form, showing a greater mesial elevation. 
Figs. 21-23. Rhynchonella (Stenocisma) carica. 344 
21-23. Dorsal, ventral and front views of the specimen described. 
Figs. 24-43. Rhynchonella venustula.... 346 
24, 25. Dorsal and front views of a small ventricose specimen. 
26, 27. Dorsal and front views of a larger but less ventricose, and more finely plicated specimen. 
28, 29. Ventral and front views of a specimen not fully grown, showing eight plications in the 
mesial sinus. 
30 - 32. Dorsal, ventral and front views of an immature individual, with a slight elevation in 
front and only four plications in the sinus. 
33. Front view of an immature specimen, showing six plications in the sinus. 
34, 35, 37-39. Dorsal, ventral, profile, front and cardinal views of a full grown and gibbous 
specimen, having only five plications in the sinus. The ventral side is denuded of the 
shell and shows the vascular markings. 
36. Enlargement of the specimen, fig. 35, to show the ramifications of the vascular lines, and 
their origin in the border of the muscular impressions. 
40, 41. Dorsal and front views of an unusually broad individual. 
42, 43. Front views of specimens which are extremely elevated in this part, with a maximum 
number of plications in the sinus. 
Figs. 44-49. Rhynchonella (Stenocisma) contracta? var. (see addenda) . 351 
44-48. Dorsal, ventral, profile, cardinal and front views of a characteristic specimen of this 
form. 
49. Enlarged ventral view of a smaller specimen, showing a greater number of plications. 
50, 5K Dorsal and ventral views of a specimen, with finer plications, resembling the R. (S'.) 
eximia. 
