108 PALEOZOIC FISHES OF NORTH AMERICA. 
The conical, compressed, ancipital tooth found in the same beds and 
described’ by Professor Leidy under the name Apedodus, resembles some 
of the teeth of Sauripteris Taylori, and may have belonged to that fish. 
Professor Zittel® includes Apedodus Leidy in Rhizodus, but no traces of 
that genus have been found in the Catskill rocks, while detached striated 
teeth resembling those of Holoptychius and Sauripteris are not uncommon. 
I am therefore of the opinion that they should be referred to these genera 
and not to Rhizodus. 
Order PLACODERMI. 
Genus BOTHRIOLEPIS, Eichw. 
A very considerable number of specimens of what is apparently a 
species of Bothriolepis have been found in the Catskill rocks of New York 
and Pennsylvania; also a less number of fragments of a smaller species in 
the Chemung group of the same region. They consist for the most part 
of body plates dismembered and scattered, and the arms in a better or 
worse state of preservation. The arms are frequently seen articulated 
with the anterior ventral plate as in Pterichthys. Each one is a compressed 
triangle in section, the base toward the body, the apex turned outward and 
forming a sharp keel, which is set with prominent enameled tubercles. 
Usually only the upper three or four inches of this organ are preserved; 
this part seems to have been a solid and homogeneous rod of cartilage covered 
with several articulating plates of enameled bone. It rapidly narrows below, 
and at first sight would be thought to constitute the entire organ, but 
spliced on to its conical extremity was a sharp and rather slender spine two 
inches or more in length. This is covered with small articulating plates 
above and is longitudinally striated below. It carries on the outer edge a 
series of relatively strong, acute denticles. 
The ventral armor of Bothriolepis apparently consisted of five plates as 
in Pterichthys, and of these the outer surface is ornamented with vermicular 
furrows separated by narrower ridges. These furrows are sometimes con- 
tinuous, sometimes interrupted forming pits of which the bottoms are often 
1 Jour. Acad, Nat. Sci., Phila., p. 164, pl. 17, figs. 5, 6. 
2? Handbuch der Palzontologie, Abtheil. 1, vol. 3, part 1, p. 182. 
