PROFESSOR OWEN ON INDIAN CETACEA. 29 
The squamosal consists chiefly of its articular or zygomatic part (PI. IX. figs. 1 & 3, 27), 
which is deep in proportion to its length, truncate, and three-sided; the outer side is 
slightly convex and rather rough, 1” 5'” in depth posteriorly; the inner side is divided 
between the articular cavity (fig. 3, g), rough for syndesmosis with the mandible, and 
the smoother surface internal to it, which extends mesiad in a triangular depressed form 
(27') beneath the back part of the alisphenoid (¢), but without joining it: the upper 
surface, of an inequilateral shape, contributes a lower wall to the temporal fossa. The 
squamous portion (fig. 1), continued upward from this facet, is triangular, with a rounded 
apex, about an inch in length, and rather more in height; it is applied against the ali- 
sphenoid (6) and parietal (7). The rough posterior tract articulating with the parietal 
(7) and exoccipital (2), and contributing to the outer wall of the otocrane (fig. 3, 07), 
I consider to be the ‘‘ mastoid” confluent with the squamosal, together forming the bone 
which should be termed ‘“‘ squamo-mastoid.” The mastoid part terminates below in a 
rough, flattened, triangular surface (fig. 3, 8), 5’ 7’” in diameter, which is divided from 
the zygomatic or articular process of the squamosal (g) by a deep fissure. On the inner 
side of the base or back part of the mastoid, in the line of its suture with the parietal, 
is the (stylomastoid?) fossa. The squamosal forms no part of the inner or proper 
wall of the cranial cavity. The glenoid or mandibul-articular surface (g) is longitu- 
dinally oblong, 1” 5’” by 8” in diameter, moderately concave, least so transversely, and 
looking inward, downward, and with a slight inclination forward. The mandible 
offers no notable peculiarity, save that which relates to shortness in proportion 
to the entire skull, concurrently with the same specific character of the upper jaw. 
The depth of the ramus at the coronoid process is relatively as great as in the longer- 
jawed species, and consequently bears a greater ratio to the length of the entire 
ramus: this in the present skull is 7”, the greatest vertical extent of the ramus being 
2" 6'"; the shallowest part of the ramus is where it supports the teeth; it deepens a 
little at the short symphysis. There are fourteen alveoli approximated in a common 
groove in each mandible, extending along 3” 3’” from the symphysis. The correspond- 
ing groove of the upper jaw (fig. 3) shows seventeen alveoli, along an extent of 36”. The 
deeper part of the alveolus is distinct in the anterior teeth ; but, as they recede, the sockets 
are indicated by depressions merely in the common groove. The teeth are slender ones: 
the anterior ones in the upper jaw average a length of 8’, two-thirds of the regular 
cement-covered, thickened, and solid base being implanted, the exposed third forming a 
smooth, partially enamelled, pointed crown, with a circular transverse section and in 
most a slight incurvation; the length of crown is from 3’” to 4”, the diameter of its 
base 1’, that of the inserted root 2’”. 
As in other Delphinidw, the bony palate is entire, save at the slight median divarica- 
tion of the maxillaries and premaxillaries, and the major part of this median fissure is 
closed by the vomer. A pair of small (neuro-vascular) foramina is situated near the 
maxillo-palatine suture, and one or two others obliquely groove and pierce the palatine 
plate of the maxillary. 
