228 PALEOZOIC FISHES OF NORTH AMERICA. 
Celacanthus robustus, Newb. Of this species no complete, nor even 
good specimens, have yet been obtained, though scales, opercula, jugulars, 
ete , are common in the cannel coal at Linton, Ohio. It was a foot or more 
in length, and apparently quite distinct from the smaller species with which 
it is associated. 
Rhadinichthys ? lineatus, Newb. The little Paleoniscoid fish which I 
described in the Palaeontology of Ohio, vol. 1, p. 853, as Hurylepis lineatus 
should be separated from that genus and probably be included in Rhadi- 
nichthys, Traquair. The same should, perhaps, be done with my Hwrylepis 
corrugatus. Both these differ from the typical species of Hwrylepis, with 
which they are associated at Linton, by the narrowness of their scales (ver- 
tically) and the linear ornamentation of all the head bones. In Huwrylepis 
proper the eranial surface is always tuberculated. In Eurylepis lineatus the 
scales on the sides are quadrangular and about as high as long. In E. cor- 
rugatus the side scales are about twice as high as long. In both these 
species the scales are smooth and polished, and over the abdominal portions 
of the body are very narrow; hence are more numerous in each vertical 
row than in the true Eurylepids. Whether they should be included in Dr. 
Traquair’s genus Rhadinichthys can be decided only by a comparison of 
specimens, which has not yet been possible. 
Euctenius, sp. At Linton I have found several specimens of what 
Prof. Anton Fritsch calls Aammplatten. He has found them in the Upper 
Carboniferous rocks near Stuttgart, and considers them the cloacal append- 
ages of Amphibians. Dr. R. H. Traquair obtained them from the Coal 
Measures of Scotland, and named them LHuctenius, supposing them to be the 
teeth of fishes. They are well named Aammplatien, for they are beautiful 
little combs half to three-fourths of an inch long, with exquisitely cut and 
polished teeth. Sometimes the comb proper is attached to a kind of handle 
as long as itself; such specimens resemble minute mandibles of fishes, like 
Callognathus, described in this memoir; I have other specimens in which 
the combs are set side by side, as many as nine or ten in a series, and two 
groups are associated in the relative positions of the palate teeth of Ctenodus. 
With these in view it will require strong evidence to convince me that these 
singular objects are not the dental organs of fishes. 
