232 
MR. W. K. PARKER ON THE STRUCTURE AND 
(al and behind this part the narrow fore corner of the parietal lies over it. The 
parietal, in this aspect, is seen as a fine shell of bone, with its hinder three-fourths 
overlapped by the squamosal. That scale is perforated at its hinder part, near the 
almost straight squamous suture. 
The squamosal ( sq .) is ribbed (or limbate), outside, the fore part of the thick edge 
being the rudiment of the jugal process, which however scarcely projects beyond the 
glenoid cavity ( gl.c .). The thick, ribbed edge dips and forms the post-glenoid tract 
behind its middle ; it then rises, and runs into the low lambdoidal crest, which is 
formed above by the interparietal (i.p.). The palatine (pa.) is hidden by the maxillary 
in this aspect, but the pterygoid (pg. ) is seen with its short, blunt hook ; the tympanic 
( a.ty .) also just comes into view. 
The dentary region of the lower jaw (d.) is not much more than half the length of 
the ramus ; it is as remarkable for its slenderness, as the hinder, shorter part is for its 
breadth. The coronoid process (c.jp.) is small, and uncinate; it is separated from the 
large, well-formed condyloid process (cd.p.) by a round notch. The angular process 
( ag.p .) is separated from the condyloid by a round notch twice as large as the upper : 
it is twice as large as the coronoid, and also uncinate; hooking towards the coronoid 
hook. Below, the angular process is notched and another third sharp hook is seen ; 
there (see also fig. 5) the bone is very thick, and both the thickening and the hook 
are curved inwards, as in Marsupials. The outer face of the broad divided part of the 
ramus is made concave by the outward leaning of the coronoid process (fig. 5). 
The lower view (fig. 1) shows the peculiar lathiness of the palatal region, the bones 
having much the character of those investing the face of the. embryo of a longirostral 
Bird. 
The premaxillaries (px.) show four parallel tracts ; the two outer are the alveolar, 
and the two inner are the palatine regions, and these are separated by a deep cleft, 
ending in a round notch in front, where Jacobson’s organs (j.o.) open in the anterior 
palatine foramina. Bight and left of the median suture each maxillary palatine plate 
is split half-way backwards to the palatine bone (pa.) ; the inner spikes bind on the 
inner spikes of the premaxillaries, and the outer splintery, interalveolar tracts bind 
against the alveolar tracts of the premaxillaries. Then each palatine plate of the 
maxillary is hollow at the mid-line, and against the alveoli, and convex along its 
middle, up to the palatine bone, which impinges upon the hinder third of the 
maxillary. This latter bone then divides into a short jugal and a long inner process. 
The hollow behind the last tooth is the infraorbital canal (V 3 .), and the small, bony 
bridge over it is seen in the distance. The palatines (pa.) are very long, nearly as 
long as the submesial part of the maxillary palatine plate; they run in under those 
tracts, first with an inner, and then with an outer spike ; only their front two-fifths is 
complete up to the mid-line, for they soon form a thick short process, which meets its 
fellow at an obtuse angle over the open nasopalatine passage. Each palatine is there 
convex, and a little broader than the open space in the middle ; the bone widens to 
