PROFBSSOE OWEX ON INDIAN CETACEA. 27 



outward, overlapping the pterygoids ( 24 ), contract where they form the fore part of the 

 foramen Lacerum anterius and the optic foramina, beyond which they expand to 

 support the orbital plate (fig. 3, n') of the frontal.' 



The frontals (PI. IX. figs. 1 «& 2, u, ir ), in great part overlapped, as in other Cetacea, by 

 the maxillaries ( 21 ), show at their narrow exposed strip, extending transversely across the 

 summit of the cranium, the per.sistant frontal suture, half an inch in length ; from this 

 suture the strip curves outward and backward, expanding beyond the interparietal ( ?» ), 

 and then downward and forward, contracting and again expanding, to form the post- 

 orbital process (figs. 1, 2, 12): this is triangular and three-sided, one facet being a 

 continuation of the exposed strip, a second contributing to the temporal fossa, and a 

 third to the orbit (or). In the temporal fossa, the frontal (fig. 1, 11 ) articulates with 

 the parietal (7) and alisphenoid (5); in the orbit (ib. or), with the orbito-sphenoid 

 (fig. 3, 10 ) and malar ( 26' ) ; then, arching forward from the postorbital process, the 

 frontal forms the superorbital ridge (fig. 1, 11), and articulates anteriorly by a kind of 

 gomphosis with the malar ( 26' ) ; it is overlapped here, as on the cranium, by the max- 

 illary (21"). The medial parts of the frontals (fig. 2, 11) are united posteriorly with 

 the interparietal ( 7* ), anteriorly with the nasals ( 15 ). 



The vomer (ib. fig. 8, 13 ) extends forward to within an inch and a half of the end of 

 the premaxillaries, and behind these it intervenes upon the bony palate between the 

 maxillaries, along a strip of two inches extent and three lines across the broadest part. 

 This palatal part of the vomer (13) is the lower convexity of the canal formed by the 

 spout-shaped bone ; the hollow of the canal is exposed at the upper interspace of the 

 premaxillaries. Here, also, is seen, two inches behind the fore end of the vomer, the 

 rough thick anterior border of the coalesced prefrontals (fig. 2, u), which contracts as 

 it passes into their upper border, forming the septum of the nostrils, expanding below 

 and behind to form the back wall of the nasal passages ( w ). At this pert a trace of 

 the suture between these foremost neurapophyses of the skull remains. Their bifid spine 

 — the small transversely extended subquadrate nasals (15) — intervenes between the. 

 frontals (u) and prefrontals ( 14' ). The palatine bones appear on the palate as narrow 

 strips (fig. 3, 20 ) wedged between the maxillaries, (21) and pterygoids (24), and united 

 together beneath the vomer by a longitudinal suture of 3'" extent : then, passing out- 

 ward and forwai-d, after a brief contraction they suddenly expand and bend upward to 

 line or form the mesial wall of the orbit, and again contract to articulate with the frontal 

 at the superorbital fossa ; the mesial borders of the palatines articulate with the vomer 

 and prefrontals ; and between the pterygoids and the vomer the palatines form the fore 

 part of the lower half of the nasal passages. The orbital plate of the palatine sends off 

 an outer thin lamina, which terminates by a free margin at the back of the orbit. The 

 palatine plates of the maxillaries (21) unite together for about an inch in front of the 

 palatines, then slightly diverge to give place to the vomer (33), which, however, docs 

 not sink to their level ; in advance of the vomer the plates slightly diverge to theii- 



E 2 



