[wHiTteaves] FOSSIL FISHES OF THE DEVONIAN ROCKS 289 
The length of the spine is 214 inches, but though the point is entire, 
some of the base has been lost, so that originally it must have been 
a little longer. It shows an antero-posterior curvature of a very much 
stronger and more pronounced description than is found in the young 
forms of any hitherto described species, and this, together with the 
great delicacy of its ornamentation, distinguishes it as new. The 
ornamentation consists of rather fine ridges passing with a very slight 
obliquity over the side of the spine; this obliquity increases towards 
the base as well as towards the anterior aspect, where the ridges are 
also rather coarser than posteriorly. The ridges are plain at the apex, 
but soon become crenulated, the crenulations being more pronounced 
on the anterior aspect. 
“ That this species belongs to the genus Gyracanthus is fully shown, 
not merely by the nature of the ornament, but by the obliquity of the 
posterior area, the prominent edge of which is armed with a row of 
minute denticles. 
“Gyracanthus has hitherto not been known to exist below the 
horizon of the Carboniferous rocks. Its occurrence in the Lower 
Devonian of Canada is therefore as interesting a fact as the occurrence 
of Cephalaspis in the Upper Devonian of the same country.” 
SUB-CLASS II. OSTRACODERMI. 
(8) CEPHALASPIS CAMPBELLTONENSIS, Whiteaves. 
Ccphalaspis Campbelltonensis, Whiteaves. 1881. Canad. Nat. & Quart. Journ. Sc., 
vol. 10, no. 2, p. 98; and (1889) Trans. Royal Soc. 
| Canada for 1888, vol. vi. sect. iv, p. 92, pl. x, fig. 2. 
5 Ai Traquair. 1890. Geol. Mag., dec. 3, vol. vii, p. 21. 
Cephalaspis Whiteavesi, Traquair. 1899. Op. cit., p. 21. 
Cephalaspis Campbell onensis, A. Smith Woodward. 1891. Cat. Foss. Vishes 
Brit. Mus., pt. ii, p 190, pl. ix, fig. 5: 
Type.—Shield ; in the Museum of the Geological Survey at Ottawa. 
When Dr. Smith Woodward visited the Museum of the Geological 
Survey in 1890, he called the writer’s attention to the circumstance 
that the anterior end of the head shield of this species had been some- 
what incorrectly described and figured. Instead of its being “ somewhat 
pointed in front and obliquely rounded at the sides anteriorly,” as 
originally described, he showed that it is really “ produced anteriorly 
into a short, narrow, sharply rounded rostrum,” as described and figured 
in 1891, in the second part of his Catalogue of the Fossil Fishes in 
the British Museum. This description was based upon specimens 
from Campbellton acquired by that institution in 1888 and 1889, one 
