26 PROFESSOR OWEN ON INDIAN CETACEA. 
The elements of the occipital have coalesced. The basioccipital (Pl. IX. fig. 3,1) 
forms the lower fifth of the foramen magnum, intervening for an extent, measured in a 
straight line, of 103 lines between the lower ends of the occipital condyles (ib. 2'): it is 
here thick and concave transversely: it becomes thinner vertically and expanded later- 
ally as it advances to join the basisphenoid (ib. 5), with which it has coalesced: a slight 
median longitudinal obtuse rising divides two large shallow concavities, from the sides 
of which the aliform expansions of the basisphenoid extend, which bend slightly down- 
ward to form the lower and inner or mesial wall of the otocrane (ib. or). The occipital 
condyles (figs. 1 & 3, 2,2’) are narrow, vertically elongate, oval convexities, wider at 
their lower half, with the mesial margin gently convex, the lateral or outer margin 
sinuous, through a slight concavity marking off the upper third of the condyle: the 
length of the condyle in a straight line is 2 1’, the greatest breadth 1” 11”: the 
upper ends of the condyles are 1” 3’ apart; they are low and sessile. The foramen 
magnum is vertically oval, widest above, and notched at the middle of the upper 
border; its length, to the end of the last notch, is 2”, its breadth 1” 3’; the breadth 
across the broadest parts of both condyles is 2 9’, The paroccipital (figs. 1 & 3,4) 
an exogenous growth of the exoccipital, forms the back part of the otocrane, towards 
which it is sinuous or slightly concave, and terminates below in a thick rough border, 
4" across the thickest part (figs. 3,4”); this border is divided by a notch from the 
otocranial plate (5') of the basisphenoid, and just within the bottom of that notch’ 
opens the canal for the nervus vagus. The superoccipital (figs. 1,2, 3) rises and ex- 
Pands, as in other Delphinid@, into a broad and lofty convex plate reaching the vertex, 
and there articulating with the parietals (7) and interparietal (7*); a low median 
ridge (fig. 2, 3) divides vertically the upper half of the superoccipital. On the inner 
surface, 1” 6’” above the foramen magnum, a vertical triangular plate of bone descends 
into the falx; it is thickest behind, where its base is grooved transversely by the lateral 
sinus. 
The alisphenoids (Pl. IX. figs. 1, 5,6) coalesce with the fore part of the lateral borders 
of the basisphenoid, in advance of the otocrane (fig. 3, 07), of which it forms the anterior 
wall or boundary: the base of the alisphenoid is notched posteriorly for the third, and 
anteriorly for the second, division of the trigeminal; it expands as it passes outward, 
slightly rising (fig. 1, 6) to join the parietal (7), and frontal (11), and to overlap the 
process of the squamosal (fig. 3, 27’), continued, mesiad, from the glenoid cavity (g). The 
suture between the interparietal (fig. 2, 7* ) and superoccipital (3) is obliterated, and that 
with the parietals is partially so. The suture between the parietal and superoccipital 
remains at its lower half (fig. 1, 7), showing that a narrow strip of the parietal appears 
on the external surface of the cranium, extending backward, between the squamosal 
(27) and superoccipital (3) to the exoccipital (2), and slightly expanding at its junction 
therewith. 
The presphenoid (ib. fig. 3,9) is distinct from the basisphenoid (5), and extends in 
the form of a compressed rostrum forward, contracting, to be enclosed by the pos- 
terior sheath-shaped part of the vomer (13). The orbitosphenoids (ibid. 10) extend 
