Dr. R. H. Traquair—Devonian Fishes from Canada. 147 
though it was clear that there was something still to be determined 
regarding the species of Cephalaspis occurring at Campbelltown. 
The mystery is quite cleared up by the specimens in the present 
collection; there are two species, but the new one is that with the 
rounded snout, which I shall describe under the name of 
Cephalaspis Jexi, sp. nov. 
Cephalic shield rounded in front, cornua incurved, comparatively 
short and stout; the orbits relatively smaller than in C. Campbell- 
townensis, situated nearly midway between the anterior and posterior 
extremities of the shield. The external ornament of the shield 
consists of minute closely set tubercles often tending to be arranged 
in concentric lines which are parallel to the borders of the tesserae. 
On the cornua the tubercles are not so close, showing intervals which 
are finely longitudinally striated. The inner margins of the cornua 
are distinctly denticulated. 
In C. Campbelltownensis, on the other hand, the front of the shield 
is produced into a pointed rostrum, the cornua are relatively longer, 
the orbits relatively larger than in the preceding species. ‘The 
ornamentation of the cornua and the denticulation of their inner 
margins is more delicate, the former consisting of minute pits 
and reticulating furrows, the interspaces between which appear as 
minute flattened tubercles. 
Both of these species seem to be common at Campbelltown, but 
perfect shields of C. Jezi are rare, being mostly broken on one side, 
or else distorted by pressure; whereas those of C. Campbelltownensis 
more commonly retain their contour complete. As the name 
Whiteavesi, having dropped, cannot according to the rules of 
nomenclature be again applied to a different species of Cephalaspis, 
I have pleasure in dedicating this new one to Mr. Jex. 
Phlyctenaspis Acadica, Whiteaves. 
Ooccosteus Acadicus, Whiteaves, Trans. Roy. Soc. Canada, vol. vi. sect. iv. p. 93, 
pl. ix. and woodcut. ; 
Phlyctenaspis Acadica, Traquair, Grou. Mac. Dec. III. Vol. VII. pp. 20 and 60, 
Pl. III. Figs. 1, 2. 
Phiyctenaspis acadica, A. S. Woolward, Cat. Foss. Fishes, British Museum, pt. i. 
p. 295. Also in Geox. Mae. Dec. IIL. Vol. VITI. 1891, p. 5. 
This collection is rich in remains of Phlyctgnaspis Acadica, among 
which are some specimens which throw fresh light upon the structure 
of this interesting and still imperfectly known genus. 
One of them shows a large portion of the ventral shield with 
nearly all its plates 7m situ, and from it, along with detached plates, 
Ihave drawn the accompanying restoration, which clears up, I think, 
certain important points recently discussed by Mr. Smith Woodward. 
This specimen shows the left anterior ventro-lateral plate and part 
of the right one, also the median ventral plate and the greater part 
of the posterior ventro-lateral plate of the lett side, and finally the 
left lateral spine or cornu in connection with the corresponding 
anterior ventro-lateral. 
