EASTMAN: CARBONIFEROUS FISHES FROM THE CENTRAL WEST. 219 
species of Homacanthus vary considerably in curvature.! The present form 
may also be compared with the spines referred by Davis and Newberry to the 
genus Hoplonchus, which is scarcely distinct from Homacanthus. The single 
American species assigned to Hoplonchus was originally described by New- 
berry as Ctenacanthus parvulus, and occurs in the Cleveland Shale (Upper 
Devonian) of Ohio. 
Formation and Locality. — Chemung Group; Warren, Pennsylvania. 
CTHNACANTHUS Aaeassiz. 
In a recent number of this Bulletin (Vol. XX XIX., No. 3), several species of - 
Ctenacanthus were described from material belonging to the United States 
National Museum, and derived from the Kinderhook limestone of lowa. Some 
of these spines had formed part of the Government display at the Omaha and 
other expositions, previous to their coming to Cambridge, and when placed in 
the hands of the writer for description the authorities at Washington were 
unable to furnish a record of the exact locality whence they were obtained. 
Since their description was published, however, information has been received 
from Mr. Charles Schuchert, who purchased the specimens, that the types of 
C. longinodosus, C. lucasi, C. decussatus, and C. solidus, together with the figured 
specimens of C. spectabilis and C. venustus, were collected by a Mr. McCabe 
-from the Kinderhook quarries at Le Grand, near Marshalltown, in Marshall 
County, Iowa. A description of the formation as exposed in this vicinity will 
be found in Volume VII., pp. 221-226, of the Iowa Geological Survey Annual 
Reports (1896). 
FRAGMENTS OF DERMAL ARMOR AND OTHER UNIDENTIFIED 
REMAINS. 
Portions of calcified cartilage, detached tubercles, bosses, and dermal plates 
are of not infrequent occurrence in nearly all members of the Mississippian 
series, being particularly abundant in the Kinderhook and St. Louis lime- 
stones ; and in a few instances nearly complete cartilaginous and osseous jaws 
have been brought to light, some of them dentigerous. None of these frag- 
mentary remains are capable of satisfactory determination, although the more 
characteristic of them have received provisional designations, such as Petrodus, 
Stemmatias (Stemmatodus St. J. and Worth. non Heckel), Mazodus, etc. The 
wide range of form and ornamentation displayed by these bodies is remarkable, 
and it is evident that Carboniferous fishes possessed a much more varied ex- 
ternal covering than their Devonian predecessors. 
The survival of- moribund Arthrodires during at least a part of the Kinder- 
hook is witnessed by occasional dermal plates displaying the structure and 
tuberculation characteristic cf this group. An examination of weathered and 
1 Trans. Roy. Dublin Soc. (2), Vol. I, p. 861, Pl. XLVIIL., Figs. 7-9. 
