PROFESSOR HUXLEY ON THE OSTEOLOGY OE THE GENUS GLYPTODON. 47 
of the fifth alveolus, while behind the sixth it ascends, somewhat abruptly, to its pos- 
terior termination. 
Throughout the posterior two-thirds of its length, the palate is slightly and evenly 
concave from side to side ; but, from the third alveolus forwards, its middle part rises to 
form a median convexity, which ends by a rough, abruptly truncated ridge (Plate IV. 
fig. 3, a ), behind the premaxillary fissure. It forms, in fact, the posterior boundary of 
a transverse fissure ending in a notch, or short canal, at each extremity, which represents 
the anterior palatine foramen, and which, taken together with the intermaxillary fissure, 
simulates very closely the form of a T. A deep groove (&) separates the raised part of 
the palate from the alveolar margin, and ends, behind, in a canal which burrows into 
the substance of the bone opposite the anterior edge of the third tooth on both sides. 
On the left side, however, the hinder part of the groove is bridged over by a bar of bone. 
Large foramina are situated, along a line continuing the groove, opposite the third and 
fourth alveoli ; but no such apertures appear in the posterior part of the palate until 
quite its hinder extremity is reached, when, on each side, two crescentic fossae (Plate IV. 
fig. 3, c), wider in front than behind, lie on the inner side of the last alveolus, and appear 
to separate the palatine from the maxillary bones. They end caecally above. 
The bony palate exhibits no distinct sutures, except a trace of a maxillary suture 
behind the anterior palatine foramen, and of a palatine suture, which widens behind 
into a cleft, separating the arcuated, divergent inner and posterior boundaries of the 
palatine bones. The free surfaces of the bony masses which bound the palate, poste- 
riorly, are so smooth and unbroken, that I suspect the pterygoid bones must be repre- 
sented in them. 
As the palate presents very nearly the same width throughout, while the roof-bones 
of the skull are always much wider than it, it follows that any vertical section of the 
skull, perpendicular to its long axis, in the palatine region, would exhibit a trapezoidal 
form, like that of the anterior nares — the predominance of the upper side over the lower 
being still more marked. But in the antorbital region the roots of the zygomatic processes 
are so large, and stand out so much from the sides of the head, that the skull, viewed in 
front, looks almost like a cube, with its lower face produced forwards and downwards 
into a truncated wedge (Plate VI. fig. 1). The only trace of a suture visible upon any 
part of the sides of the facial wedge is an almost obliterated one (Plate V. fig. 1, a), 
which runs from a slight notch, opposite the level of the anterior palatine foramen 
and in front of the first alveolus, upwards and slightly backwards, and marks off the 
ascending process of the prsemaxilla from the maxilla. This ascending process, very 
narrow in the middle, widens above and joins the nasal bone, so that the circumference 
of the anterior nares is completed by the prsemaxillse and nasal bones only. 
Opposite the second and third alveoli, the maxillary bone, as I have stated; above, 
widens out and expands into the root of a stout zygomatic arch, whence a process, nearly 
6 inches long by 2 inches wide, passes directly downwards. The process is much flattened 
from before backwards (Plate VI. fig. 1), and is arched from above downwards (Plate V. 
mdccclxv. i 
