DENTITION OF SOME DEVONIAN FISHES 
DurING the last few years our knowledge of the multiplicity 
and relationships of the Middle and Upper Devonian fish-faunas 
in this country has been enlarged by the discovery of much new 
material. Exceptionally interesting finds have been made in 
the Marcellus, Hamilton, and Naples shales of New York, the 
Chemung-Catskill of Pennsylvania and its presumable equivalent 
in Johnson county, Iowa, in the Corniferous of Ohio, and in the 
Hamilton limestone of Wisconsin and adjoining states. From 
-the last-named horizon notable collections have been brought 
together and rendered accessible for study by Messrs. E. E. 
Teller and C. E. Monroe and the late T. A. Greene of Milwaukee, 
and Professors Calvin and Udden of the Iowa State Geological 
Survey. These have been freely drawn upon in the preparation 
of the following notes. 
GENUS DINICHTHYS, NEWBERRY 
So intimately related are the two best-known Arthrodires, 
Coccosteus and Dinichthys, that the only crucial test of generic 
distinctness is afforded by the dentition. Likewise, for the 
discrimination of species, dental characters are all-important. 
Among the body-plates the chief distinctive characters are fur- 
nished by the dorso-median and clavicular. 
1. D. pustulosus E. (Fig. 1).— Although remains of this 
Hamilton Dinichthyid are tolerably abundant, nothing was 
known of its dentition until recently, when one large premax- 
illary, nearly equaling that of D. ¢errelli in size, and two max- 
illary or shear-teeth were found by Mr. Teller in the hydraulic 
cement quarries of Milwaukee. Last falla fragmentary mandible 
showing rudimentary denticles along the posterior slope of the 
cutting edge was obtained from the Hamilton of New Buffalo, 
Iowa, by Professor Udden, and still more recently Mr. Monroe 
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