Dr. R. H. Tra quail* on a new Species 0 / Gyracanthus. 417 
The species 4, 5, 6. 7 were originally described under the 
genus Acunthodrilus (see my article in Quart. Journ. Micr. 
Sci. xxxii.), but have been transferred on account of their 
possessing two gizzards and a genital fossa. 
October 17, 1890. 
LI. — On a new Species o/ Gyracanthus. 
By R. H. Traquair, M.D., F.R.S. 
In their recently published c Catalogue of British Fossil 
Vertebrata’ Messrs. Smith Woodward and Sherborne state con- 
cerning the spine from Burdiehouse figured by Hibbert (Trans. 
Roy. Soc. Edinb. xiii. pi. xi. fig. 1), and referred by Agassiz 
to his Gy r acanthus for mosuS) that it u is of doubtful species.” 
This spine is in the collection of the Museum of Science and 
Art, and I had long been of opinion that neither it nor any 
other specimen of Gyracanthus from the Calciferous Sand- 
stone series could be referred to ihe same species as that from 
the Coal-measures figured by Agassiz as such (Poiss. Foss, 
t. iii. tab. v. figs. 2-6), and which, on the other hand, must 
also include his G. fonnosus. Lately a considerable number 
of Gyracanthus spines have occurred in the u Dunnet” shale 
at Straiton, which clearly belong to the same species as those 
from Burdiehouse, and enable one to have a still better idea 
of its characters and configuration. 
Those spines resemble G . formosus (inch tuberculatus) in 
the nature of their ornament, and though most of the Burdie- 
liouse specimens are eroded and worn, that figured by Hibbert 
has the tuberculation of the ridges in places exceedingly well 
marked. But from G. formosus the species differs in having 
the basal or inserted portion very small, and again in the 
usual want of that lateral curvature which is so constant a 
feature in all examples of that species which have attained 
any size. The antero-posterior curvature is usually present, 
but only in one specimen out of many have I observed any 
pronounced lateral flexure. Like Cr. formosus they are fre- 
quently worn at the tips, and all are bilaterally unsym- 
metrical. 
As there is no doubt that we have here a species which 
has not hitherto been named or defined, I propose for it the 
name of Gyracanthus rectus . 
Not uncommon in the Calciferous Sandstone series of the 
east of Scotland. Besides Burdiehouse and Straiton, the 
following localities may be noted : — Burntisland, Pittenweem, 
St. Andrews. 
Ann . & Mag* N, Hist . Ser. 6. VoL vi. 
30 
