FISHES OF THE CARBONIFE..OUS SYSTEM. 113 
firm the conclusions of Professor Hall in regard to the specific, if not gen- 
eric, distinctness of this fish, and can add something to his description. 
The pectoral fin figured by Professor Hall is too imperfect for satisfac- 
tory study, but it was probably in part covered with scales (lobed) like the 
paired fins of Holoptychius. 'The scales have the same general character 
with those of that genus; that is, they are circular, subquadrate, or elliptical 
in outline, from one anda quarter to two and a half inches in greatest 
diameter, the covered portion beautifully reticulated with large elongated 
meshes, the exposed portion thickly set with fine conical or rounded 
granules, generally without linear arrangement. he external surfaces of 
the bones composing the pectoral arch, as well as those of the head, are 
ornamented with short, strong, flexuous, enameled ridges, and rounded or 
triangular tubercles. The jaws are set with conical, compressed, striated 
teeth, resembling that described by Professor Leidy under the name of 
Apedodus. The external surface of the dentary bone is for the most part 
occupied with fine granulations like those of the scales, but more widely sepa- 
rated. ‘Toward the lower border the ornamentation is coarser and similar 
to that upon the clavicles; the surface of some of the head bones is granu- 
lated like the scales. 
The general structure of Sauripteris is essentially that of Holoptychius, 
and it would not be at all surprising if the discovery of more complete 
material would compel the union of the two genera. 
Houoprycurus Americanvs, Leidy. 
Plate XIX, Figs. 12, 13. 
The scales to which the above name was given by Dr. Leidy had been 
previously regarded as identical with those of Holoptychius nobilissimus, 
Ag., of the Scotch Old Red Sandstone. This is not surprising, for some of 
the scales from the caudal portion of the body of H. nobilissimus are undis- 
tinguishable from these in size, form, and markings; but, as any one can see 
from a glance at the magnificent plate given of this species by Agassiz,! 
most of the scales have a reticulated marking quite different from any yet 
found in this country. Hence it is certain that Dr. Leidy’s species is not 
' Mon. des Poissons Fossiles, etc. (Old Red Sandstone), pl. 23. 
MON XVI--——5 
