FISHES OF THE CARBONIFEROUS SYSTEM. 22h 
Ohio, volume 2, page 410, Pl. XLV. I had previously obtained a more 
nearly complete cranium of this fish, and I now give below an outline sketch 
of it, half natural size. 
The reference of these crania 
to Ctenodus is not based upon the 
discovery of teeth associated with 
them, but upon their marked re- 
semblance to the crania figured 
by T. P. Barkas in his Atlas of 
Carboniferous Fossils, Pl. X, Figs. 
944-246, and upon descriptions of 
the remains of this genus by Han- 
cock and Atthey in the Annals 
and Magazine of Natural History, LES, 
and in the Transactions of the Fic. 3. Ctenodus Ohicensis, Cope. Outlines of cranial plates ; $ 
Tyneside Naturalist’s Field Club. aa 
On the preceding pages of this memoir I have pointed out the diffi- 
culty we find in separating Dipterus, Ctenodus, and Ceratodus by the teeth 
alone; but it is probable that the crania, where available, will furnish satis- 
factory distinctive characters. In this connection a comparison of the figure 
of the tessellated cranium of Dipterus, given by Pander in his Ctenodipte- 
rinen, Pl. III, Fig. 1, with the diagram now published, will be suggestive. 
Though very much alike, it will be seen that they present differences which 
may well have generic value. 
I will conclude my remarks on our Coal Measure fishes with a few 
notes on species which have been imperfectly described elsewhere, or which 
are new but can not be fully described without more material. 
Celacanthus ornatus, Newb. This is a small species found at Linton, 
Ohio, where it is very rare. It is briefly described in the Paleontology of 
Ohio, vol. 1, p. 340. Since the publication of that volume I have obtained 
several other specimens and find that it may be readily identified by its | 
small size, relatively large cranial tubercles, and very thin, delicate scales 
on which the raised lines are parallel and do not converge as in C. elegans and 
C. robustus. 
