368 Messrs. Hancock & Atthey on Reptile- and Fish-Remains 
spines are very similar to, but they seem to be smaller than, 
those of the other species, as pointed out by Sir P. Egerton ; 
they. also appear to have the surface more elevated and 
rounded. : 
From the character of the scales and great size of the pec- 
toral spines, but more particularly from the difference observed 
in the teeth, we consider ourselves justified in dividing this 
from the A. Wardi, and beg to dedicate it to Sir P. Egerton, 
who was the first to point out the probability of its specific 
distinctness. We therefore propose for it the name of Acan- 
thodopsis Egertont. 
Gyracanthus tuberculatus, Agassiz. 
The gigantic spines of this little-understood fish occur 
pretty frequently at Newsham and Cramlington in a fine state 
of preservation. In conjunction with Mr. J. W. Kirkby, one 
of the authors of this paper pointed out in 1863 that these 
spines were not, as usually thought, dorsal, but were paired 
spines, most probably pectoral*. We have now before us 
seventy-one of these formidable weapons; and the first thing 
that strikes the observer is, that by far the greater number 
have lost the apical extremity, and that they are not merely 
bent from front to back, but are also laterally curved. On 
closer examination it is found that there are as many bent to 
the right as to the left side, and that of such bent spines there 
are just twenty-four pairs. Thus twenty-three spines are left 
unaccounted for; these may be considered straight, being bent 
only from front to back, and their points are entire. But first 
respecting the paired spines: we have said that they have all 
lost their points; they are not fractured, however, but are all 
worn smoothly down diagonally at a very acute — and, 
what is still more interesting, this wearing always takes place 
at the side opposite to that of attachment. Assuming, there- 
fore, that these spines are pectoral, and that they were inclined 
backwards and downwards, as assuredly they would be, then 
the wearing of the points is exactly such as would take place 
oy their coming in contact with the ground. And, again, the 
largest or oldest spines are uniformly the most worn; some, 
indeed, are reduced to mere stumps. In one such specimen 
now before us, which is seven inches in circumference, and 
which must have been one of the very largest, only ten and a 
half inches are left. Another example, six inches in circum- 
“* See Pe entitled ‘‘ Fish-Remains in the Coal-measures of Durham 
and Northumberland,” by Messrs. T. Atthey and J. W. Kirkby, read in the 
Geological Section at the Newcastle Meeting of the British Association. 
