38 Dr. R. H. Traquair on the 
only an antero-posterior curvature and in which the apex was 
entire and pointed. The former set, which could also be 
arranged in pairs, they regarded as pectoral, the latter as 
dorsal*., 
The occurrence of numerous spines of this genus in the 
Blackband Ironstone of Borough Lee, near Edinburgh, having 
lately induced me to inquire into the whole subject of Gyra- 
canthus, I was surprised to find that, among the numerous 
specimens which came under my observation from that and 
other localities in Seotland, there was not one which was 
bilaterally symmetrical, and which consequently could be 
assigned to a median position. On this subject I published 
a few remarks in the ‘Geological Magazine’ for December 
1882. To pursue the subject further it was, however, abso- 
lutely necessary to reexamine the specimens in the Atthey 
collection, now in the museum at Newcastle-on-Tyne. And 
having recently visited that city, I must here express my 
cordial thanks to my friends Mr. W. Dinning, Secretary of 
the Newcastle Natural-History Society, Mr. R. Howse, 
Curator of the Museum, and Mr. J. Hancock, member of com- 
mittee, for the kind and liberal manner in which they afforded 
me every facility for examining the specimens in that remark- 
able collection of Coal-measure vertebrate remains. 
Although I have not seen the original type of Agassiz’s 
Gyracanthus tuberculatus, 1 have no hesitation in referring to 
it the great majority of the specimens from Newsham in the 
Atthey collection, and they form, indeed, a most beautiful and 
instructive series. And as no systematic description has been 
given of this form since the time of Agassiz, who had only a 
drawing of a mere fragment to go upon, it will not be out of 
place to enter somewhat into detail as to the configuration of 
these spines. 
Proceeding first to the consideration of those labelled 
“ pectoral” in the Atthey collection, one very fine example is 
153 inches in length by 2} in diameter at its widest part near 
the base; its distal extremity is obliquely truncated or worn 
off on the anterior aspect, and the whole spine, when looked 
* In a paper on Z)istychius, published in the Ann. & Mag. Nat. Hist. 
for September 1883, My. T, Stock states, with regard to Messrs. Hancock 
and Atthey’s views as to the pectoral ‘nature of certain Gyracanthus- 
spines, that he has “been able to confirm their conclusions by the finding 
of an interesting specimen containing well-preserved remains of the 
pectoral arch,” and refers to a paper on the subject, read by himself to the 
Edinburgh Naturalists’ Field Club. However, on consulting the paper, 
now published (Trans. Kdinh. Nat. Field Club, vol. i. pt. 2, pp. 50-61), 
it turns out that the ‘“ pectoral arch,” in this case, is Messrs, Hancock 
and Atthey’s “ carpal bone,” of which more anon. 
