ANATOMY OF BALDEN OPTEE A BO STB AT A. 
211 
lay between and separated the superior maxillae, where it assisted in forming the roof 
of the mouth. This ridge was sharp behind, rounded in front, and partially covered 
by the palate-bones posteriorly; in front it was overlapped by the superior maxil- 
laries: the external edge of each lateral plate fitted into a groove which was situ- 
ated on the nasal aspect of that bone. Posteriorly it became very thin and flattened, 
and was separated from the basisphenoid by a small interval, into which the rudimen- 
tary rostrum was projected. On either side it united by schindylesis with the base of 
the internal pterygoid process, where it formed the upper and internal wall of each pos- 
terior naris ; more anteriorly it united with the frontal, sending a small process between 
that bone and the pterygoid, which entered into the suture between the palate, alisphe- 
noid, and frontal bones ; still further forwards its outer edge united with the ethmoid 
by harmonia. The deep channel on the upper surface was occupied posteriorly by the 
nasal lamella of the ethmoid bone, more anteriorly, in the recent state, a thick firm 
fibrocartilage completed the septum narium, and occupied this sulcus as far forwards as 
the extremity of the bone. 
The palate-bone was quadrilateral in outline and exhibited two surfaces. First, a 
superior or vomerine, which presented a ridge that fitted into a groove on the vomer ; 
and second, an inferior or palatine surface, which was smooth and concave, and formed 
the posterior superior wall of the palate. Of the edges of the palate-bone, the posterior 
was convex and presented a series of plates, by which it was articulated to the anterior 
surface of the alisphenoid by a similar arrangement of lamellae. The inner border was 
smooth and rounded behind, where with its fellow of the opposite side it formed the 
inferior boundary of the posterior nares ; its outer edge was sharp, and was adapted to 
the contiguous surface of the superior maxilla, and the anterior border was short 
and flat. 
The intermaxillary bone was long, narrow, and somewhat twisted ; anteriorly it was tri- 
quetrous, but its posterior third was flattened and presented but two surfaces. Its ex- 
ternal surface was convex anteriorly, but as it passed backwards, the bone being, as it 
were, twisted on its long axis, this surface finally looked directly inwards, where it also 
became concave to accommodate the opening of the anterior nares. For the anterior two- 
thirds of its length its internal surface was concave from side to side, broad in the centre, 
gradually narrowing anteriorly to the point of the upper jaw, and behind to a sharp 
ridge, which represented this surface on the posterior third of the bone. The inferior 
surface was also laterally concave and channelled deeply behind for the reception of the 
upper edge of the superior maxilla ; one vascular foramen, looking downwards and for- 
wards, was found on the outer surface of the left bone only. 
The three edges bounding these surfaces were sharp, convex, and irregular ; posteriorly 
the bone was flattened and formed a single lamina, which was fitted into a sulcus in the 
frontal, internal to the nasal process of the superior maxilla, and external to the nasal 
bone ; its anterior part or apex projected for nearly 3 inches in front of the superior 
maxilla. 
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