98 PALEOZOIC FISHES OF NORTH AMERICA. 
Agassiz says of the specimens of Phyllolepis, ‘that they are not unfre- 
quently met with in the Old Red Sandstone of Clashbennie, Scotland, but 
are generally incomplete; often rolled as well as torn.” This is also the 
case with the plates of Holonema, and I can not but think they are generic- 
ally identical." 
Formation and locality: Chemung group; Bradford County, Pa. Col- 
lected by Mr. A. T. Lilley. 
DinicuTHys TUBERCULATUS, Nl. sp. 
Plate XXXII, Fig. 3. 
In the fish beds of the Chemung conglomerate at Warren, Pa., Mr. F. 
A. Randall and Mr. C. E. Beecher have obtained numerous fragments of 
the plates of a Placoderm which is closely allied to, if not identical with, 
Dinichthys. Aside from a large number of unintelligible fragments of plates 
once evidently of considerable size (because they are from one-quarter to 
one-half an inch in thickness) the greater part of two supra-scapular plates 
and the anterior half of a dorsomedian are sufficiently well preserved to 
merit description. The supra-scapular plates have essentially the form of 
those of Dinichthys Terrelli, viz, are trapezoidal, and have a similar though 
still more prominent condyle projecting from the anterior margin for artic- 
ulation with the angle of the head Also, as in the larger species of Di- 
nichthys, a straight and deeply incised line runs from the base of the articu- 
lating condyle to the posterior border, traversing nearly the middle of 
the plate. The portion of a dorsomedian referred to above also has pre- 
cisely the structure of that of Dinichthys, viz, it is evenly arched in outline 
posteriorly and carries a strong keel on the under surface which terminates 
behind in a neck-like process projecting downward. These characters 
justify me in associating these spécimens with the species of Dinichthys. 
They present, however, one character not yet noticed in any other member 
of the genus, viz, the exposed surfaces of the plates of the head and body 
were strongly tuberculated. This is a character which has given its name 
1Since the above description was written I have seen in the collection of M. Max Lohest, of 
Liege, Belgium, a number of scutes of a small species of Phyllolepis apparently ideatical with this. 
They were from the Psammite de Condroz, the equivalent of our Chemung group. 
