38 PROFESSOR OWEN ON INDIAN CETACEA. 
The maxillary (Pl. XII. fig. 1, Pl. XIII. figs. 1 and 2, 21) forms the major part of the 
bony roof of the mouth: a small triangular strip of the premaxillary (Pl. XIII. fig. 2, 22) 
is wedged into the short anterior interspace between the maxillary (2) and vomer (13'). 
The palatal surface (21*) is moderately convex transversely, straight lengthwise, and 
is impressed by an alveolar groove (q/) retaining one socket and tooth (Pl. XII. 
fig. 1, 2) at the fore end and continued in a straight line backward for 3 inches 
(rather more on the left, rather less on the right side) without indications of 
alveoli, and in a line not parallel with the outer margin of the bone, but receding 
to a distance of 1 inch from it, posteriorly; so that the teeth, if developed there, would 
be rather palatal than marginal in position. The outer border of the maxillary thickens 
near the malo-maxillary fissure (21, /), with a smooth convex exterior. That fissure dilates, 
as it sinks obliquely backward and inward, to a breadth of from 3 lines to 4 lines, its 
depth being 1 inch 6 lines (4). These fissures mark off the rostral portion of the skull, 
which is here an equilateral triangle, including above (Pl. XIII. fig. 1) parts of the 
yomer (13), prefrontal (14), premaxillaries (22), and maxillaries (21): the surface so formed 
is concave transversely at its posterior three-fourths, almost straight longitudinally. The 
maxillary, expanding backward beyond the rostrum, bends (at /, fig. 1) round the upper 
and back part of the malo-maxillary fissure; and in close conjunction (here partial con- 
fluence) with the malar (26), it forms the large smooth tuberosity (21,26) external to 
the fissure: from the tuberosity the convex raised border of the posterior expanded 
plate of the maxillary comes into connexion with the frontal (11), whence it subsides 
to form a deep hollow as it sweeps inward to rise again upon the bifurcate sinuous ridge 
(ib. 15,15”) which divides this singular postnarial tract, or spermacetic cavity, of the upper 
surface of the cranium. ‘The total breadth of this cavity is 6 mches 4 lines, the posterior 
three-fourths of its circumference, so bounded by the maxillaries and describing as much 
of a circle, being a little produced backward, subangularly, at the hindmost part: the 
open anterior fourth is continued upon the more shallow concavity of the triangular 
rostrum. The right maxillary is vertically pierced by two foramina (Pl. XIII. fig. 1, a, 2), 
which converge to the common inferior outlet (ib. fig. 2,d). The upper fissure between 
the maxillary and premaxillary widens and deepensas it extends backward, and terminates 
in the canal (fig. 1, ¢), also conducting to the fossa (fig. 2, d), which, as it transmits 
maxillary branches of the fifth pair from the orbit to the exterior of the skull, is 
homologous with the antorbital foramen of other mammals: the altered position of the 
outlet, as regards the orbit itself, is the result of the reflection, so to speak, of the facial 
surface and nasal plates of the maxillaries upon the forehead above and behind the 
orbits. 
The pterygoids (Pl. XIII. fig. 2, 24) meet at the midsurface of the roof of the mouth, 
and extend the palatine suture (p/) backward beyond the palatine bones (20). From this 
line each pterygoid extends outward and backward, and divides mto an internal and 
external pterygoid plate: the former terminates in a short triedral process, representing 
