146 CTENACANTHUS, A-SPINE OF HYBODUS. 
a ape brief manner the external characters of two varieties. 
s I take to be a corroboration of the opinion I arrived at 
indepen tly. 
apers treated only of the fact of the teeth of 
Behosas be g found in the upper Coal Me s, but inci- 
dentally I hibetioated that the teeth of Hybodus and Cladodus 
were discovered comparatively frequently associated with the 
spines of Ctenacanthus, and that from that and other circum- 
puted spine of Ctenacanthus. ord t there might not 
be the slightest doubt as to the veritableness of the spine of 
Hybodus from which the sections fi cal examination 
portions of an undoubted spine; they very graciously suppli 
me with the required specimens, and it is from them that I made 
my sections. With regard to the sections of the spine of 
Ctenacanthus being undoubted, I may state that the remains of 
the spines that I “destroyed to make them are in Mr. T. P 
arkas’ possession, and also that the sections were cut from five 
or six different spines, and from different portions of those 
spines. 
remarquer par 
et des caractéres extérieurs trés-caractéristiques. Ils sont géné- 
ralement wn peu arqués,+ plus gros et plus ae vers leur base 
qua leur extrémité, et se terminent en une pointe plus ou moins 
*Although I consider Aas ee — to pertain to Hybodus, I shall 
keep the ori iginal names throughout this paper, with the tnderstanding that 
ybodus andi in the Coal Measures, and that Hybodus 
pore to the : > spines obtained from the Lias, Wealden, Xe. 
+ The italies in these quotations are my own 
