FISHES OF THE CARBONIFEROUS SYSTEM. 125 
fin-rays are in place also show a bulbous expansion of the proximal extremity 
of the spine, which apparently signifies an articulation; a natural feature in 
a pectoral spine, but never present in those of the dorsal line. In the Berea 
grit itself, at Berea, Independence, and especially at Chagrin Falls, Ohio, 
have been found numerous specimens of Palwoniscus Brainerdi, which some- 
times attain a length of fifteen or sixteen inches and not unfrequently are 
found entire. 
In the pyritous layer of the sandstone at Berea Dr. Clark has obtained 
numerous specimens of three species of Clenacanthus* (Ct. formosus, Ct. 
Clarkii, N., and Ct. angustus, N.), of which descriptions will be found in 
another part of this memoir. It is somewhat remarkable that with these 
spines no teeth have as yet been discovered. 
In the calcareous bands of the Bedford shale Mr. H. Hertzer discovered 
years ago a species of Cladodus (C. Hertzeri),’ which has the peculiarity 
that the external denticles are smaller than the intermediate ones, and these 
in their turn smaller than the central ones. This is perhaps a character 
which has generic value, but as the specimen upon which the specific 
description was based remains unique, I have hesitated to erect a genus 
upon a foundation so narrow. 
In the Cleveland shale farther down the river Drs. Clark and Gould 
have obtained some of the most interesting remains of fishes yet found in 
Ohio. These are the cranium, dorsomedian plate, suprascapulas, and man- 
dibles of Vitanichthys Clark (the largest known Placoderm), and the same 
bones and plates of a small species of Dinichthys (D. Gouldii), in which are 
preserved the eye-orbits, surrounded by circles of four sclerotic plates, 
both of which will be found described in another part of this memoir. 
Mr. Jay Terrell also and earlier found a cranium with the supra- 
scapulas, clavicles, mandibles, etc., of Titanichthys Agassizii in the Cleve- 
land shale on the banks of Black River. 
Dr, R. H. Traquair, of Edinburgh, has separated from the genus Palwoniscus certain species 
which have relatively small dorsal fins, set behind the middle of the back, with striated scales and 
teeth bent at an angle, under the name of Gonatodus. It is probable that Palwoniscus Brainerdi should 
be included in this category, but I have not yet seen any specimens in which the teeth were sufficiently 
well preserved to show whether they have the peculiar character which Dr. Traquair has made diag- 
nostic of his genus. 
2 Described in Palwontology of Ohio, vol. 1, p. 328, pl. 36, fig. 2; vol. 2, p. 53, pl. 59, fig. 1, 
3 Paleontology of Ohio, vol. 2, p. 46, pl. 58, fig. 5. 
