THE 
AMERICAN GEOLOGIST. 
Vol. XVIII. OCXaBER, 1896. No. 4 
[PAL.EONTOLOGICAL NOTES FROM BuCHTEL COLLEGE, No. 13.] 
DINICHTHYS PRENTIS-CLARKI. 
E. W. Claypole, Akron, O. 
(Plato VII.) 
During the season of 189.5 Dr. Clark found a specimen which 
he considered a new species of Dinichthys. He showed it to 
me, and upon close examination there remained little doubt 
that his opinion was well founded. Its leading characters are 
accordingly given in the present note. Fortunately a consid- 
erable portion of the cranial armour was found, so that more 
details can be given of this than are known of some of the 
species hitherto described. 
From almost all the known forms it is readily distinguished 
by obvious difterences. Two onlj'^ resemble it so closely as to 
render confusion possible. These are D. (jouldi and D. i)i- 
termedius. Of the former the mandible is only imperfectly 
known. But this shows a long cutting blade and merel}- a 
rudiment of the second cusp, whereas in the fossil now in 
hand the latter, though lost, was obviously present in life as 
shown by its remaining base, and the cutting edge of the man- 
dible was apparently siiort. But in regard to the latter char- 
acter, the broken condition of its upper edge makes a positive 
statement on this point impossible. The opinion expressed 
above is, however, supported by the beveled margin of the 
maxillary hereafter to be mentioned. 
