542 Dr. R. H. Traquair—Fish-Remains from Borough Lee. 
perforate projection upon the inner surface of the tergum. (Mr. John 
Young’s Collection.) 
Fic. 7. Spheroma gigas, Kerguelen’s Island. 
», 7a. Front view of head. 75. Half of the same enlarged to show pore (p.) 
5, 8. Serolis paradoxa, Sandy Point, Straits of Maghellan. Showing pore (p) 
near margin of thoracic somite. 
III. —Notice oF New FISH-REMAINS FROM THE BLACKBAND IRONSTONE 
oF BoroucH Les, NEAR HEpinspureu.—No. IV. 
By Dr. R. H. Traquair, F.R.S., F.G.S. 
Gyracanthus nobilis, n.sp. 
ITHERTO I have been in the habit of referring the Gyracanthus 
spines commonly occurring m the Borough Lee Ironstone to 
G. formosus or tuberculatus of Agassiz, being disposed to believe in 
the specific identity of those two forms, as has already been suggested 
by Messrs. Hancock and Atthey, and hinted at by Agassiz himself. 
In fact, the salient point of difference between the two is the greater 
extent of the tuberculation of the ridges in the latter, while in the 
former it is principally seen on the proximal parts of the ridges, which, 
as they converge towards the anterior middle line of the spine, become 
first simply undulated and then smooth. The original figured specimen 
of G. tuberculatus is from the Coal-measures of Sunderland ; that of 
G. formosus is from the same formation at Dudley ; but though Agassiz 
refers to it as occurring also at Burdiehouse, in Midlothian, and 
Burntisland in Fifeshire, it seems to me very doubtful if these 
Calciferous Sandstone specimens are really the same. And certainly 
the study of a large quantity of additional material from Borough 
Lee has convinced me that the species of Gyracanthus characteristic 
of this Ironstone of Carboniferous Limestone age is specifically 
different from both formosus and tuberculatus. 
These spines are elongated and rather slender, showing very little 
lateral curvature, though every specimen and every fragment which 
I have examined shows that marked want of lateral symmetry which 
I have described in my last communication on the Borough Lee 
fossils. The posterior ridge is strongly denticulated, save in worn 
specimens. But the salient specific mark lies in the disposition and 
mode of tuberculation of the sculptured ridges. Commencing at the 
proximal end of the spine, these ridges are at first strongly and 
closely tuberculated along their whole extent, but near the closure 
of the posterior sulcus or hollow, this close tuberculation becomes . 
limited to the anterior aspect,—each ridge as it arises, and advances 
upwards and forwards, showing first a comparatively distant tuber- 
culation, then a smooth space (sometimes very minutely crenulated) 
on the side of the spine, and then becoming thick and coarsely tuber- 
culated as it turns round to the front aspect. Where this feature of 
the ridges commences, they also become excessively oblique and very 
delicate, and in some specimens they occasionally also bifurcate along 
the sides of the spine, but in front where the tuberculation appears 
they become coarse, and curve a little forwards so as to become also 
less oblique. Towards its extremity the ridges become entirely smooth 
