FROM THE YOREDALE SERIES. Gol 
enamelled. The under surface concave, Teeth probably palatal 
and not very thick. 
Cyrronobus GisBus, Davis, sp.n. (Plate XXVII. figs. 1 & 6.) 
Teeth. Semirhomboidal in outline, greatest length 1:25 inch, 
breadth 0-75 inch. Anterior portion of tooth raised transversely, 
forming a prominent gibbous ridge, from which the surface descends 
gradually, with a gentle convexity, to the anterior margin ; posteriorly 
the surface is first depressed, forming a deep sulcus, and thence 
extends evenly to the posterior extremity. The anterior margin is 
rounded, forming an obtuse angle with that of the superior portion 
of the posterior one. The latter narrows rapidly, and forms with 
the opposite margin an acutely pointed extremity. The lower edge 
of the ridge is broad and terminally imbricated. The surface is 
uniformly enamelled, and covered with small punctures; parallel with 
the superior margin there are four or five broad imbricated folds of 
enamel, possibly indicating the direction in which the tooth has 
increased in size. ‘The under surface is slightly hollowed or concave. 
A superficial observation of the specimens would lead to the 
inference that the posterior portion of the tooth was the base or root, 
the gibbous part being the crown; but that this is not the case is 
demonstrated by the extension of the minutely punctured enamel 
uniformly over the whole surface. 
Genus Ecurnopts, Davis, g. n. 
Teeth. Base consisting of a more or less circular mass, convex 
laterally ; surface enamelled and coarsely punctate. From the upper 
part of this base spring rows of denticles, probably three in number, 
one along the central line and one parallel with this on each side. 
The denticles are about equal to one third the diameter of the 
tooth in length; they are conical, laterally compressed, acuminate, 
enamelled and smooth. 
Ecuinopus parapoxus, Davis, sp.n. (Plate X XVII. fig. 7.) 
Teeth. A comparatively large mass, more or less circular in form, 
from which spring three small, conical, acutely pointed denticles. 
Greatest diameter 0°6 inch. The surface from which the three 
denticles arise is flat and 0-4 inch across ; remaining portion convex, 
its surface covered with rugose punctures. At a distance of 0-15 
inch from the denticulated margin there are two or three circular 
depressions, of the same diameter as the base of the existing den- 
ticles or cusps, and apparently the impressions of previously existing 
denticles which have been broken off. The denticles are all similar 
in size, and extend radially from the surface, 0-1 inch in length, 
their diameter at the base being equal to about half the length ; 
they are smooth, round at the base, becoming laterally compressed 
and flattened nearer the apex. They are separated from each other 
by a distance slightly greater than the diameter of the base, 
: 2u2 
