606 GEOLOGY OF OHIO. 



DINICHTHYS, Nby. 



Of this genus of strange fishes that inhabited the earfy sea of Ohio 

 the first described and the typical species, as already mentioned, was 

 that found by the Rev. H. Hertzer in 1864, and named by Dr. Newberry 

 D. Hertzeri. It is still the oldest known Dinichthys (excluding one 

 doubtful form), having been found in the Huron Shale about 500 feet 

 below all the rest of its congeners in Ohio. The shape of the mandible 

 and its dentition proclaim at once its relation to the Coccosteids, but its 

 size surpasses nearly tenfold the largest Coccosteus hitherto described. 



Not until some 3<-ears later was another member added to this ancient 

 family and then it came from the Cleveland Shale on the shore of Uake 

 Erie, where Mr. J. Terrell found another species with still more extraor- 

 dinary dentition. In this species, D. Terrelli, the jaws are not set with 

 teeth along the upper edge as they were in the older form but close one 

 on another as a pair of shear-blades, the upper one cutting outside. 



Since then D. Goulai, named after its discoverer, D. intermedins 

 and D. cur his have been added to the list, all of about one-half the size of 

 the older species, and all showing the shear-blade dentition of D. Terrelli, 

 D. corrugatus and D. minor are still smaller species whose dentition is 

 not yet fully known. The fragments found do not prove the presence 

 or absence of the cutting shear-blade. Of D. tuberculatus only a few 

 plates have been found and these do not include the jaw. They came 

 from the Chemung near Warren, Pa. It is noteworthy that this species 

 is said by Dr. Newberry to be identical with one found near Ljege, in 

 Belgium, and now in the collection of Prof. Lohest of that University. 

 If so it is probably the only international species of fish yet found in 

 Ohio. 



All these additions to the Dinichthyid family, except the last, have 

 come from the Cleveland Shale of Northern Ohio. 



It is very doubtful if the dorsal plate from the Corniferous Limestone 

 called D. pr&cursor will prove to belong to the genus when its other parts 

 are known. 



Of D. Ringnebergi {minor), from the Portage Group of N. Y., only 

 a single dorsal plate has been described, and D. Newberryi is represented 

 \>y the mandible only. 



In addition to the above a single premaxillary tooth (of N.)was 

 lately described by Mr. Whiteaves from the Upper Devonian of Snake I, 

 in Iy. Winipegosis, Manitoba, and this, named D. Canadensis, with a 

 doubtful D. Eifelensis from Belgium, completes the list of named and 

 described species of this genus down to date so far as the writer is aware. 

 After this chapter was put into type three additional species were de- 

 scribed by the writer in the American Geologist for December, 1893. 



A New Species of Dinichthys. 

 In Dr. Clark's collection is a single mandible of a Dinichthys which 

 I cannot identify with anv of those already described and am therefore 



