56 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 20, 



in extricating entire the skull, arid in relieving it from the surround- 

 ing closely adherent matrix, and subsequently in working out the 

 other bones above specified. 



Description of the Skull : Plate II. — The skull is moderately 

 long, slender, tapering gradually from the zygomatic region to the 

 muzzle, PI. II. fig. 2, with an unusually straight upper outline, from 

 the occipital crest to the end of the nasal bones, PI. II. figs. 3 and 4. 

 The bony rim of the orbit, fig. 3, or, is incomplete behind for an ex- 

 tent of about one-fifth of its circumference. 



The occipital region is triangular, bounded by a strong occipital 

 crest, 3, which is continued on each side into the upper border of the 

 zygomatic arch, PL II. fig. 3, 27, and, by the middle of its upper 

 part, with a parietal crest, 7. This latter, rising clearly above the 

 calvarian surface, PI. II. fig. 4, to an extent of from one to two lines, 

 advances forward one inch nine lines, and bifurcates, subsiding to the 

 level of the frontal surface, 11, each division diverging and curving 

 outward, with the convexity forward, to the post-frontal process, 12, 

 which projects backward and a little downward, terminating freely 

 about 8 lines above the zygoma, 26, 27. The interorbital part of the 

 frontal region, ib. 11, is nearly flat at its middle, and bends gently 

 down on each side to the superorbital border. The long nasals, is, 

 form the rest of the upper surface of the skull, which is at first mo- 

 derately convex transversely, and is then grooved along the mid-line 

 to the free ends of the nasals. These bones are 13 lines across their 

 base, and gradually contract to a breadth of 7 lines, which they re- 

 tain for the terminal inch of their extent. 



The zygomatic arch, springing outward and a little forward from 

 its hinder root or pier, PI. II. fig. 3, 27, describes a slight sigmoid 

 flexure, first convex then concave upward, where it forms, 26, the 

 lower border of the orbit ; this border extends some 4 or 5 lines 

 further outward than the upper border. There seems not to have 

 been a zygomatic process rising toward the postfrontal, 12, but a 

 mere convexity of the upper border of the zygoma behind the orbit. 

 The extreme vertical diameter of the zygoma is 4 lines. The cerebral 

 part of the cranium forming the inner wall of the temporal fossa 

 shows the greatest expansion of the brain at about the middle of that 

 fossa, behind which, on both sides, the concavity exhibits several 

 irregular indentations and some vascular perforations. There is no 

 superorbital foramen ; a very feeble indent of the base of the post- 

 orbital process is the sole indication of the place of issue of the super- 

 orbital nerve. The antorbital foramen, PI. II. figs. 3 and 4, a, about 

 1J line in diameter, is situated 9 lines in advance of the orbit, and 

 between 2 and 3 lines above the alveolus of the second premolar. 



The vertical outer plate of the maxillary, 21, slightly expands where 

 it forms the sockets of the small canine, c. The sides of the bony 

 nostril are almost straight, extending from a distance of 5 lines from 

 the free ends of the nasal, o, obliquely downward and forward, and 

 being formed by the premaxillary bones, PL II. fig. 4, 22 : the ver- 

 tical extent of the aperture is about 10 lines. 



