29 
articular immediately in front of the quadrate articulation 
for the M. adductor mandibule is much more marked on 
this side, where the muscle is naturally larger and, 
further, the distortion of the jaws to the eyeless side is 
assisted by a tendon from it inserted into the maxilla. 
The dentary of this side bore 22 teeth, as against 3 on the 
right side. 
Maxilla.— Distinctly larger and more curved than the 
right but not so robust. At about a third from the head 
on the posterior edge is an eminence for the attachment of 
a stout tendon arising in connection with the M. adductor 
mandibule, and the action of which tends to draw the 
jaws towards the eyeless side. This eminence and tendon 
are not conspicuous on the ocular side, and indeed in the 
Sole, where the ocular is also the right side, the tendon is 
stated by Cunningham? to be absent on the eyeless side, 
although the muscle is said to be larger on that side. The 
eminence is figured and the muscle described by Tra- 
quair,t who calls the latter the Retractor Maxille.* At 
the head of the maxilla on the posterior side the bone 
articulates directly with the free anterior extremity of the 
palatine instead of by the interposition of a short liga- 
ment. The cap of cartilage gliding over and above the 
head of the vomer is larger and the terminal free facet is 
also more extensive. The whole action of the jaw appa- 
ratus is markedly asymmetrical owing to the unpaired 
mesethmoid prominence separating the two maxillary 
facets being obliquely set towards the right. Hence when 
the maxille are depressed they follow an oblique direction 
towards the left or eyeless side. The articulation of the 
maxilla with the pre-maxilla is also modified on this side. 
On account of the motion of the jaws towards the left the 
+ The Common Sole. Plymouth, 1890, p. 48. * Op. cit., p. 279, Tab. 30. 
* Cp. also Allis, Jour. Morph., xii., pp. 552 and 576. 
