136 



PALEONTOLOGY. 



as in fig. 56, they characterize the genus JStobates. Fossils of 

 this genus occur in the English eocenes and the Swiss mol- 



lasse. 



In the " crag" of Norfolk and Suffolk, and in marine plio- 

 cene beds, fossils have been found which closely resemble 

 the osseous and spinigerous plates that beset the skin of the 



Fig. 56. 



^Etobates subarcuatus. 

 (Eocene, Bracklesham). 



Fig. 57. 



Raia clavata. 



(Dermal spines). 



kind of ray called "thornback" (fig. 57), and which indicate 

 the existence of a pliocene species allied to the Raia clavata. 



The almost entire specimens from the lithographic slates 

 of Solenhofen (Thaumas alifer, Mst.) and of Cirin (Spathobatis 

 bugesiacus, Thiol.) shew a form of body which, like that of the 

 modern monk-fish (Squatina), connects the rays with the 

 sharks. Squaloraia has the like annectant relationship with 

 the saw-fish (Pristis), which, as now specialised, first appears 

 in eocene beds (Pristis bimlcatus from Sheppy, and Pr. acuti- 

 dens from Bagshot sands). The Cyclobatis, Eg., from the ter- 

 tiary limestone of Lebanon, resembles the modern torpedos, 

 a true and formidable species of which (Torpedo gigantea, Ag.) 

 has left its remains in the rich repository of ichthyolites at 

 Monte Bolca. 



Thus we obtain evidence of fishes of the plagiostomous 

 order in the marine deposits of every formation from the 



