48 
CHIMJSKOIDEI. 
five or six small, irregularly arranged, isolated patches ; 
the oral aspect of the small anterior tooth (x.) is marked 
with large, parallel, transverse, mammillated ridges. 
Enniskillen Coll. 
P. 151. The complete dentition exposed from above, and partly from 
below, associated with three dermal plates; noticed by 
the present writer in the Ann. Mag. Nat. Hist. [6] vol. iv. 
(1889), p. 278. The specimen is shown, of the natural 
size, in PI. II. fig. 2, and the parts are marked in accord¬ 
ance with the following description. The mandibular 
teeth ( md .) are both shown from the inner and oral aspect, 
though partly obscured by the overlying palatines ( pi .) ; 
and, so far as preserved, each seems to be precisely similar 
to the corresponding tooth in the group No. P.477 (PI. II. 
fig. 3). The presymphysial tooth, situated close to the 
position of the mandibular symphysis on the opposite side 
of the slab, is considerably crushed and broken, and thus 
appears relatively broader and more flattened than in the 
fossils described above. The palatine teeth {pi.) are large, 
thin, and plate-like, but unfortunately only exposed from 
the attached surface. Each of these teeth is elongated 
antero-posteriorly and must have originally possessed a 
nearly straight outer margin, somewhat thickened, and 
sharply deflected; the short anterior margin, forming an 
acute angle with the outer, is likewise deeply deflected 
and abuts against the vomerine tooth ; but the inner and 
posterior margins are thin edges of nearly equal length, 
and there is no appearance of the close apposition of the 
right and left teeth in the median line. If the attached 
surface be approximately parallel to the oral surface in 
these teeth, there is a longitudinal median elevation, and 
this gradually disappears in the broad posterior extremity 
of the plate. The triangular vomerine tooth (v .) on each 
side is also seen to be thin and plate-like in form, its 
robust appearance, when viewed from the oral aspect, 
being due to the sharp deflection of all the margins. The 
pair of small anterior teeth ( x ) in advance of the vomerine 
is somewhat displaced; but the oral aspect of one (PI. II. 
fig. 2 a) is well displayed, and exhibits the characteristic, 
mammillated, transverse ridges, consisting apparently of 
laminated dentine. Purchased, 1880. 
