TAB. XX. 



Fig. 

 1. 



Dentalium costatum, page 188. 



a. specimen, natural size, from 



Cor. Crag. 



b. transverse section of the same. 



d. fragment, with angular ribs, 



from Red Crag. 



e. var. striatum, magnified, show- 



ing the termination without 

 a cleft. 

 /. portion magnified, showing the 

 medial dorsal cleft and divided 

 epiphragm. 



2. Dentalium entale, j». 189. 



a. var. tarentinum. 



b. var. vulgaris. 



Fig. 

 5. 



3. Dentalium bifissum, p. 190. 

 b. posterior termination, 

 enlarged. 



much 



Caecum mammillatum, p. 116. 



a. var. vulgaris. 



b. var. subulatum. 



c. posterior termination, much 



enlarged. 



10. 



11. 



Caecum trachea, jo. 115. 



a. posterior termination, much 

 enlarged. 



Caecum glabrum, p. 117. 



a. posterior termination, much 

 enlarged. 



Caecum (?) incurvatum (?), p. 117. 



a. entire figure, much enlarged. 



b. spiral portion, much enlarged. 



Patella vulgata, p. 183. 



a. view from above. 



b. lateral view. 



Chiton fascicularis (?), p. 185. 



a. end view. 



b. view from above. 



Chiton strigillatus, p. 186. 



a. penultimate (?) valve magnified. 



b. terminal valve magnified. 



Chiton Rissoi (?), p. 186. 



a. primal valve magnified. 



b. central valve magnified. 



c. terminal valve magnified. 



The lines indicate the size of the specimens. 



