PLATE 52 



Fig. I. Gampkacatitlnis uddeni (LindaM). Spine in matrix; natural size. E 1875, 

 p. 164. 



Fig. 2. Ctenacanthus wrighti Newberry. Fragment of a spine showing character- 

 istic ornamentation. X i^. E 1904, p. 161. 



Figs 3, 5. Gyracanthns sarlei, n. sp. Type, E 2487, p. 142. 

 3. Proximal half of spine, in matrix; | size. 

 5. Cross-section, X 5. 



Fig. 4. Gyracanthiis sp. Spine, X ij. E 2489, p. 144. 



302 



