PLATE 71. 



Fig. 1. 1. Onchus deweii. ( Pag. 320.) 



1 a. A fragment of shale, retaining the base of the spine, with about two inches of the lower portion, and 

 the impression beyond this nearly to the apex. 



1 6. A fragment, retaining the impression of the base and lower portion of the spine of the preceding spe- 

 cimen, with the higher portion of the spine itself. 



1 c. The basal portion of a much larger specimen, showing very distinctly the ornamented surface and con- 

 stricted base. 



1 d. An enlargement from the surface of 1 c. 



