MI ALL : BONES OF CTENODUS. 
289 
ON SOME RONES OF CTENODUS. BY PROF. L. C. MIALL. 
FOR many years past teeth and bones of Ctenodus have been accumu- 
lated in various public and private collections, and it may be useful to 
those who possess such collections to set clown briefly some of the 
identifications already made. A short statement of the facts now 
accessible respecting- the organisation of the genus will render it 
easier to place any newly discovered fragments, and may, I venture 
to hope, stimulate some of the members of this Society, whose 
local opportunities are far greater than is at present imagined, to 
search for fresh materials. The fish-bearing shales of the York- 
shire Coal-field have proved productive of interesting fossils when- 
ever they have been diligently examined, and much yet remains 
to be dug out and compared — how much a glance at the following 
very imperfect sketch of one of the most noteworthy and most 
abundant of Coal Measure fishes will show. The facts here record- 
ed are derived from the examination of specimens belonging to the 
Earl of Enniskillen, the Natural History Society of Newcastle-on- 
Tjme, the Leeds Philosophical and Literary Society, J. W. Davis, 
Esq., of Halifax, John "Ward, Esq., of Longton, and T. P. Barkas, 
Esq., of Xewcastle-on-Tyne. I have to thank the owners of these 
collections for permission to examine their examples of Ctenodus 
at leisure and simultaneously. Other important collections I have 
examined in passing, but without adequate time to work up the re- 
sults in the present memoir. One example at least of each bone 
figured is contained in one or other of the collections named above. 
In most cases I have been able to compare several examples and 
to prepare an outline which, without being in any respect hypo- 
thetical, is more complete than the best of the fossils upon which 
it is founded. 
Hinder Part of Skull (upper surface). Several good ex- 
amples of the ossifications of this region have occurred. The 
