VOL. XXVII.] PHILOSOPHICAL TRANSACTIONS. 5/3 



protuberance of the sinus for the eye, it runs straight backward, being arti- 

 culated with that part of the os frontis which forms the aforesaid lower edge of 

 the sinus for the nervus opticus, for the space of 18 inches, where it begins 

 to be overlaid with a lamina of the bone, which forms the upper and back part; 

 whence it descends 9 inches, till it comes to the root of the teeth, where 

 we shall leave it, and return to the fore-named protuberance ; from whence 

 having made up a part of the sinus for the globe of the eye, as is said, it runs 

 backward 6 inches, and is articulated by a flat suture, which first descends 

 4- inch, then runs obliquely backward 2-i- inches, with the os zygomaticum. At 

 its beginning it is 24- inches broad; plain on its inner, and convex on its outer 

 surface; bended, as it descends, like a horn, and terminating in a point. From 

 the lower part of this suture it becomes much thicker; and having framed a 

 sinus about 4 inches long, it runs toward the fore part of the skull. From 

 this sinus, as it has returned 3 inches, is formed the side of an oval hole, 

 which running from before to behind, is about 3^ inches long, and from the one 

 side to the other 2 inches. At that side which is framed by the os maxillae, and 

 toward the processus zygomaticus, it is 2 inches thick; and at its other side, 

 it runs straight backward from the os maxillae, in a direct line, with the great 

 cavity, which contains the muscles that move the lower jaw and proboscis. 

 This hole is analogous to that in a human skeleton in the os maxillae, beneath 

 the orbit of the eye; and is larger in quadrupeds, being designated for trans- 

 mission of a vein, artery, and the superior branch of the second division of the 

 5th pair of nerves, which in those go to the upper lip and jaw ; but in this 

 subject, as I have already shown at large, it is probable they serve for the 

 nourishment and other functions of the proboscis. 



The two cavous bones on each side the choana, are filled up from the two 

 firm, solid, white, weighty teeth ; the back one does not grind, but serves as 

 it were a wedge, to keep that before firm in its place. This tooth runs ob- 

 liquely backward 3 inches from the fore tooth. That part of it which is with- 

 out the jaw bone is half round, being 6 inches in surface from its root on the 

 one side to that on the other, very smooth like glass. The length of each of the 

 teeth is 7 inches. These teeth are not alike on both sides ; for that on the right is 

 but 1 inch without the alveolus, throughout its whole extent on the outer side; 

 and on its inner, it is 1 inch protuberant at its fore, and 2 inches at its back 

 part ; whereas that on the left side is only ] inch protuberant before on the 

 outside, and 3 inches behind, where it forms a kind of angle, as it is joined 

 with the hind tooth; and on the outside it is 4- inch protuberant before, and 

 2 inches behind. The tooth on the right side grinds with that of the lower 

 jaw, throughout its whole extent ; whereas that of the left, after it has run 

 back 6 inches, runs up with a half round surface 2 inches, before it is joined 



