PYCNODONTIDJi. 
269 
1878, pt. ii. p. 92, pi. iv. figs. 5, 6), probably belongs to Coccodus. 
The specimen best displaying the teeth, now in the Stuttgart 
Museum, may even belong to the typical G. armatus, but the teeth 
of its inner flanking series are relatively broader than those in the 
British Museum fossil, no. P. 4742. 
TVeV/T ™ ° H - Cu) ?- P-- 
Genus XENOPHOLIS, Davis. A»w. /«At» 
[Trans. Roy. Dublin Soc. [2] vol. iii. 1887, p. 548.] 
Trunk comparatively elongated and head large. Head and 
opercular bones ornamented with tubercles and fine ridges, and a 
large, ascending, laterally compressed, bilaterally symmetrical spine 
fixed upon the occipital region of the cranium ; teeth smooth, rounded 
within the mouth, pointed and prehensile in front. Neural and 
hsemal arches of axial skeleton of trunk robust, but not expanding 
sufficiently to encircle the notochord. Pelvic fins relatively large ; 
dorsal fin occupying at least the hinder half of the back, and the 
anal somewhat less extended, arising more posteriorly. Abdominal 
region, and middle portion of caudal region, covered with large 
imbricating rhombic scutes, each with one diagonal raised into a 
keel and terminating in a point behind. 
The present writer is acquainted only with two specimens refer¬ 
able to this genus—the type described below, and the other in the 
Court Museum, Vienna. The latter is best preserved, exhibiting 
the occipital spine and part of the dentition. 
Xenopholis carinatus-, Davis. 
1887. Xenopholis carinatus, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. iii. p. 549, pi. xxix. fig. 4. 
Type. Imperfect fish ; British Museum. 
The type species, attaining a length of about 0*18, as yet imper¬ 
fectly definable. Dorsal fin with not less than nineteen, anal fin 
with about sixteen rays. Scales relatively large, the dorso-ventral 
series above the origin of the anal fin comprising only T eight or nine ; 
those of the caudal region apparently confined to its middle, but 
continued quite to the base of the caudal fin-rays. Each scale 
with a small transverse keel terminating in a median or inferior 
acumination at its hinder margin, and the ornament consisting of 
more or less nodose parallel ridges diverging antero-superiorly 
and antero-inferiorly from this keel; ornament of the external 
bones similarly consisting of nodose ridges or series of acuminate 
tubercles. The ridge-scale at the origin of the anal fin produced 
