ON SOME MESOZOIC FOSSILS. 
7 
as to be held securely only by the teeth of the comparatively feeble 
young or so large as to need piecemeal severance by them, would 
struggle in vain against the firmer grip of the adult jaw or be 
swallowed intact. 
The anterior nares are flanked by an ascending process from 
the maxillaries and roofed over anteriorly by a pair of nasals. The 
nasals are short, o mm. fore and aft, with a transverse breadth of 
27 mm. ; close to the orbit a tongue from them bends down to meet 
the maxillary process in a horizontal suture ; the prefrontals, 11 mm. 
long on their common suture and 26 mm. on the margin of the 
orbit, more than half of which they constitute, send down from 
their anterior angles a process which cuts off that from the nasals 
from the canthus orbitalis, and shares with it its junction with the 
maxillary ; the fronto-parietal suture was effaced by the down- 
thrust of the bone anterior to it, it has an approximate length of 
15 mm. ; laterally it forms, as usual, the posterior margin of the 
orbit ; the deformed orbit is an elongate oval, 46 mm. in length, its 
vertical diameter reduced by pressure is 19 mm. ; sclerotic piates 
have so far not been divulged by removal of matrix to some depth ; 
the tympanic cavity, distorted and on its posterior margin some- 
what obscure, appears to have been continuously surrounded by 
bone, no sign of an interruption in it is perceptible ; its present 
shape is that of an oval, 33 mm. long and 20 high, drawn out to a 
point on the upper part of its posterior end. In this skull also con- 
ditions do not favour the discrimination of the remaining cranial 
elements. The surface of the bone in both skulls is rather densely 
pitted, smooth, unimpressed by tegumentary scutes, unrelieved by 
reticulating ridgelets save that on one of the parietals of the adult 
there faintly appears a small patch of them. 
Mandible. — The mandible in articular connection with the 
quadrates is apparently a member of considerable strength, 107 mm. 
in length, in span posteriorly 49 mm. While development between 
the rami was in progress the terminal part of the hinder end of the 
right one, though distant, became dislodged in so fortunate a 
manner that the form both of its own articular surface and that of 
the quadrate became ascertainable ; the former is, after adding to it 
a little left by it on the quadrate, seen to be convex, the latter con- 
cave. The end of the left ramus was found to have been broken 
into before burial with the result, long deferred, that the relics of 
