TAB. XX. 



Fig. 



1. Dentalium costatum, joa^e 188. 



a. specimen, natural size, from Cor. 



Crag. 

 h. transverse section of the same. 



d. fragment, with angular ribs, 



from Red Crag. 



e. var. striatum, magnified, showing 



the termination without a cleft. 

 /. portion magnified, showing the 

 medial dorsal cleft and divided 

 epiphragm. 



2. Dentalium entale,/;. 189. 



u. var. tarentinum. 



b. var. vulgaris. 



3. Dentalium bifissum,jfj. 190. 



h. posterior termination, much en- 

 larged. 



4. Caecum mammillatum, JO. 116. 



a. var. vulgaris. 

 h. var. subulatum. 



c. posterior termination, much en- 



larged. 



Fig. 

 5. 



10. 



11. 



Caecum trachea, ^j. 115. 



a. posterior termination, much en- 

 larged. 



Caecum glabrum,/). 117. 



a. posterior termination, much en- 

 larged. 



Caecum (.') incurvatum (?), jy. 117. 



a. entire figure, much enlarged. 



b. spiral portion, much enlarged. 



Patella vulgata, ^;. 183. 



a. \'iew from above. 



b. lateral view. 



Chiton fascicularis (?),/». 185. 

 «, end view. 

 b. view from above. 



Chiton strigillatus, JO. 186. 



a. penultimate (?) valve magnified. 



b. terminal valve magnified. 



Chiton Rissoi (?), JO. 186. 



a. primal valve magnified. 



b. central valve magnified. 



c. terminal valve magnified. 



The lines indicate the size of the specimens. 



