Sxcrion IV., 1907. EN] Trans. R.S.cC. 
IIl.—A New Genus and a New Species of Silurian Fish. 
By G. F. Matruew, LL.D., D.Sc. 
(Read May 16, 1907.) 
Some twenty years ago the author described and figured some 
peculiar fish plates found in the Silurian rocks of the Nerepis hills 
near St. John, N.B., Canada, in the Transactions of this Society,’ which 
had been more briefly referred to in earlier publications.’ 
At this time the author had in his hands, collected at the same 
locality, an imperfect specimen of another small fish, which was with- 
held from publication in the hope that better examples might be met 
with. 
In the succeeding years no better specimens of this fish have been 
procured, and it is now described, imperfect though it is, to make 
known this rare and ancient type of vertebrate. 
CTENOPLEURON * NEREPISENSE, n. gen. and sp. 
The fossil consists of the hard parts of most of the trunk and a 
few bones of the head. The posterior part of the tail is wanting. 
The fish was fusiform in shape and the part preserved is 40 mm. 
long and 13 mm. wide; it is about 8 mm. wide where the piece of 
the tail is broken off; it is lying on its side, but twisted somewhat at 
the front, so as to show a part of the belly, and the parts shown are 
mostly those of the right side, the fish having been cleft through the 
middle in splitting the shale in which it is imbedded. The fossil has 
been somewhat distorted as the ventral line from the anus to the head 
is within the margin of the body; this makes the fish seem narrower 
at the front than it really was. 
Body.—If one were to depend upon the number and size of the 
bones of the head that have been preserved, the head was quite small. 
And the belly would seem to have been short in proportion to the length 
of the fish, as the anus was only 20 mm. from the front end of the body 
as preserved in the stone. 
Head.—The narrowing of the body toward the front would seem 
to indicate that this part of the body was small, and it is more obscure 
than the rest, because the bones or plates are mostly buried in the matrix 
and, as a rule, only the edges of these protective pieces come in view. 


1Trans. Roy. Soc. Can, 1st Series, vol. vi, p. 49. Pl. iv. figs. 1 to 4. 
2 Can. Rec. Sci., 1886, pp. 251, 323, and Bull. Nat. Hist. Soc. of N. Brunswick, 
1887, op. 1. 
*Comb-like side in allusion to the prominent ribs and spines. 
