28 
which, however, contrary to those of the opposite side, 
were placed nearer the posterior edge of the pre-maxilla 
than the anterior. Dorsally this arm is closely connected 
with the left pre-maxilla. The posterior arm passes back- 
wards over the inter-maxillary, with which it is closely 
connected. At the junction of the two arms a process is 
sent backwards which is both capped with cartilage and is 
covered by a further loose moveable piece. This process 
fits into the excavation on the maxilla already described, 
and hence the pre-maxilla here overlaps the maxilla. 
Inter-Maxillary Cartilage (/.4/.C.).—This cartilage 
plays an important part in the movement of the jaws. It 
is asymmetrical, blunt in front but more pointed behind, 
and forms as it were a pivot on which the two maxillary 
bones on each side turn. It fits into the depression very 
obvious in the dried cranium above and to the !eft of the 
mesethmoid prominence, and glides up and down from 
this depression over the prominence itself. Its posterior 
surface is obliquely grooved, and in such a way that as it 
moves downwards it passes obliquely over the prominence 
towards the eyeless side—thus further assisting in the 
torsion of the jaws to that side. 
Eyeless Side. 
Articular, Angular and Meckel’s Cartilage —The two 
former are slightly larger than the right, and are also 
shghtly more densely calcified, but the differences are 
small. Meckel’s cartilage was in the specimen now 
described 2mm. longer on this side. 
Dentary.—Appreciably larger and more densely caleci- 
fied, and is strongly curved whilst the right is almost flat. 
The forking of the posterior margin is further very 
unequal, the lower limb being much the larger (ep. fig. 5). 
The depression at about the middle of the outer tace of the 
