35 
NOTE ON HYBODUS 0BTU8US, Ag: 
During the course of the present year, a spine of Hyhodus 
was found in the Coralline Oolite of Malton. Particular interest 
attaches to this spine as it is the first, so far as I know, recorded 
for the Corallian rocks of Grreat Britain. Unfortunately no 
teeth were found with the spine, consequently it was difficult to 
assign a specific name to it. Two species are given in Mr. 
Hudleston’s table of fossils * as occurring in the Corallian rocks 
of Yorkshire : hence to have given it a new name might have 
been to have added to a synonomy which is already a byword, 
while to have assigned it to either species would have been 
even more unsatisfactory. The two species in question are 
H. ohiusus Ag., and an unnamed species which is compared to 
H. grossiconus Ag. Some of the larger teeth in our own 
collection certainly do hear a strong resemblance to H. grossiconus, 
but after a careful examination there did not seem to me 
sufficient grounds for making a specific distinction between them 
and the smaller teeth—which have always been referred to 
H, ohtusus. Through the kind assistance of Mr. Chadwick, of 
Malton, I was enabled to see a large series of Hyhodus teeth, 
and I was driven to the conclusion that these teeth and those in 
our own collection belonged to hut one species. I was very glad 
to have this opinion endorsed by Mr. William Davies to whom 
I submitted the series. Acting on his advice, I have figured 
15 specimens of the series. (Plate I., fig. 1—15) in order to 
shew the striking diversities of form that exist. The absence 
of associated sets leaves us, unfortunately, quite in the dark as 
to the dentition of the species. Since, then, but one species has 
hitherto been found in the Yorkshire Corallian rocks (which, be 
it remembered, have been well explored) we may not unreason¬ 
ably refer the spine now under consideration to that species; 
and as H. ohtusus has hitherto been regarded as a Corallian 
species (it is the only Corallian species given by Morris in his 
catalogue), the spine must be considered as that of H. ohtusus. 
But I should here say that I can see no satisfactory grounds for 
identifying the Hyhodus of our Corallian rocks with H. ohtusus 
of Agassiz. That author figures two specimens, both from the 
* Proc. of the Geol. Assoc., Oct., 1878. 
