40 PROFESSOR OWEN ON INDIAN CETACEA. 
ing downward and forward: the surface is rather convex at the anterior border from 
behind forward, and is very slightly concave in the rest of its extent; it is smooth and 
with an ill-defined circumference: the anterior boundary, which also forms the posterior 
one of the lower outlet of the temporal fossa, is concave : the wall (Pl. XII. fig. 1, 27') which 
the squamosal contributes to the posterior and internal part of the temporal fossa (#) 
expands as it bends forward to join the parietal (7) and frontal (11): the suture with 
the superoccipital (3) is close to the upper boundary of the fossa; that with the 
exoccipital (2) continues a short way beyond the squamosal, and indicates the extent of 
the exoccipital. On the outer part of the base of the zygomatic or articular process the 
bone is tuberous, and represents the mastoid (8); behind the articular surface it is 
roughly excavated (PJ. XIII. fig. 2, 8"), where it contributes, with the paroccipital (4), 
to the otocranial cavity'. 
In the interior of the cranium (Pl. XIV. fig. 1) the upper or epencephalic surface of 
the basioccipital is moderately concave, and is bounded laterally by a short, obtuse, longi- 
tudinal ridge, directed mesiad, which may be where the exoccipital suture ran: the outer 
or lateral beginning of the tentorium receives a short angular ossification, which forms 
the outer wall of the fossa (v), perforated by the vagal and acoustic foramina, both of 
which pass directly outward to that at the back part of the fundus of the otocranial 
cavity (Pl. XII. fig. 1, Pl. XIII. fig. 2, e). A small branch channel from the vagal one 
opens upon the outer surface of the exoccipital at the groove which runs to the cleft 
(Pl. XII. fig. 2, 7) between the otocranial plates of the basisphenoid (5) and paroccipitals 
(4). At the fore part of the tentorial process (Pl. XIV. fig. 1,v) is the foramen of 
a canal which opens outwardly upon the alisphenoid: it is too small for the carotid, and 
may have given exit to a vein. I cannot discover any distinct entocarotid canal, any 
more than a distinct foramen ovale, foramen rotundum, or foramen opticum: they all 
seem here to be confounded in the intersphenal fissure (PJ. XIII. fig. 2, tr). From the 
extreme shortness of the jaws, the nerves of sensation to the face must have been very 
small. The “sella” (Pl. XIV. figs. 1 & 3), scarcely impresses the basisphenoid: its best 
antero-external boundaries are afforded by the superoptic processes of the orbitosphenoid 
(ib. n). There is no ossification of the falx?, no trace of olfactory foramina. The great- 
est diameter of the cranial cavity is in the direction of breadth. 
The lower jaw (Pl. XII, fig. 1, 29-32) is 7 inches 4 lines ina straight line from the back 
‘ «The squamosal is a comparatively small, but strong and thick, triangular bone; the upper end repre- 
sents the expanded squamous part in land mammals, and is articulated by broad, dentated sutural margins to 
the frontal and exoccipital: its anterior border is grooved for the reception of the alisphenoid: the lower angle 
is as it were truncated, and presents a rough surface for the attachment of the petro-tympanic: a short, 
obtuse anterior angle bends forward and represents the zygomatic process: the under surface presents a 
smooth shallow cavity for the condyle of the lower jaw: the inner border of the glenoid surface is produced 
downward into a slender process.” —Physeter macrocephalus, op. cit. p. 444. 
* In the Great Cachalot “a strong medial crest is produced forward from the inner surface of the super~- 
occipital” (Joc. cit. p. 442), 
