258 
SELACHII. 
P. 2798. Group of postero-lateral teeth, and shagreen. 
Enniskillen Coll. 
P. 2796. Portions probably of the three hinder series of teeth 
(nos. vii. to ix.), with very low crowns, shown, of the 
natural size, iu PI. X. fig. 15. In the teeth of the small 
terminal row the longitudinal crest gradually rises to a 
median eminence, and there are only faint indications of 
one or two lateral points on each side. The teeth of the 
sec and row are more than three times as long as these, 
and the principal eminence, which is narrow and pointed, 
is placed at about one third of the length of the crown 
from its anterior extremity ; the lateral cusps vary in 
their relative prominence, and are three or four in number 
anteriorly and about eight posteriorly. The third series of 
teeth is too imperfect for description, but there is distinct 
evidence that the median coronal elevation is much larger 
than in the series behind. The number and proportions 
of the superficial wrinkles upon the crown vary consider¬ 
ably, but they are often sparse and delicate. 
Enniskillen Coll. 
The following small specimens are not certainly determinable, but 
may pertain to young individuals of this species :— 
P. 2797. Obscure remains of the jaws, branchial arches, and other 
cartilages, with the scattered dentition, and part of a 
“/S phenonchus.” Two of the teeth are shown, of the 
natural size, in PI. X. figs. 6, 7, and they are all re¬ 
markable for the fewness and prominence of the coronal 
wrinkles. Enniskillen Coll. 
P. 3168. The crushed head and anterior portion of the trunk of a 
small Hybodont, probably to be regarded as a young indi¬ 
vidual. The skull must have originally measured about 
008 in length; and the first dorsal fin-spine attains a 
total length of 0*095, inserted at a distance of about 0*2 
from the end of the snout. The remains of the head are 
exposed from below, displaying the characteristic basi- 
occipital region of the cranium and portions of the man¬ 
dibular and hyoid arches, with a few scattered teeth. The 
right ceratohyal is shown, slightly curved, very broad and 
large, attaining a length of about 0-06; but the precise 
outlines of the other elements are obscured. The teeth 
exhibited have sharp, broad, coronal cusps,—one principal, 
