[wairgeaves] FOSSIL FISHES OF THE DEVONIAN ROCKS 263 
specimens show Mr. Whiteaves’s “rostral” plate, which is evidently 
the equivalent of that which I have called anterior ethmoidal in 
Coccosteus decipiens. 
“The difference in the form of those bones of the cranial shield 
seems to me certainly to be of generic importance, and I doubt not 
but that many other important differences would be apparent were the 
remains more complete. (I may remark that the plate figured by Mr. 
Whiteaves as a ventro-median (?) plate cannot be so, as it is not 
bilaterally symmetrical.) I therefore propose for it the generic name 
Phlyctenus.” 
The Geolcgical Magazine for February, 1890, contains a paper 
by Traquair, entitled “On Phlyctenius, a new genus of Coccosteidæ.”? 
In this paper the cranial shield of that genus is described in much 
fuller detail, and restored outlines of the head shield of two specimens 
each of P. Acadicus and P. Anglicus are given, to show the arrangement 
of the plates, and the lateral line with its sensory grooves. One of 
these outlines is here reproduced on Plate IV. 
The results of this paper are summed up in a new definition of 
the genus, and of its typical species P. Acadicus, also with a very brief 
description of an English species of the genus, under the name 
P. Anglicus. The new generic definition is as follows :— 
“ Genus Phlyctænius.—Cranial shield more ovate than in Coccosteus ; 
constituent plates anchylosed, except the ethmoidal; median occipital 
elongated, pointed in front and wedged in between the posterior ends 
of the oblong or ovate central plates; orbital excavation looking more 
anteriorly than in Coccosteus; course of main lateral-line groove 
nearly straight from the external occipital to tne post-orbital, where 
it is very acutely bent backwards. Plates of body-cuirass imperfectly 
known.” 
In a note at the end of this paper, the generic name is changed to 
Phlyctænaspis, as Phlyctenius was found to be pre-occupied. 
The following description of the genus Phiyctenaspis is given in 
the second part of Dr. A. Smith Woodward’s “ Catalogue of the Fossil 
Fishes in the British Museum,” published in 1891. 
“ Head and trunk broad, the dorsal aspect more or less arched 
from side to side; scutes ornamented with stellate tubercles and those 
of the upper surface of the head also marked with deep sensory fur- 
rows. Elements of cranial shield, except the rostral bone, fused 
together in the adult, and the occipital bones constituting not more 
than half of its total length; median occipital elongated antero- 
posteriorly, and its anterior end produced between the divergent hinder 
Sec. IV., 1907. 16. 
