MEGALOXYX. 9 



Between the two processes ju.st described ii wide and deep arch is Ibrmed, within 

 which is visible the external auditory meatus. This has a vertically oval aperture 

 bounded inferiorly by a rugged V-shaped auditory process. 



The face is relatively much shorter in advance of the orbit than in Alylodon, the 

 Ai, and the Unau. Over the position of the first molar tooth it presents a convexity 

 curving in the course of the latter downward and forward ; and above this for a 

 short distance it forms a nearly vertical plane, but its upper part is convex. Over 

 the position of the posterior four molar alveoli it is slightly convex, and from the 

 obtrusion of the teeth appears undulant. Between the position of the first and 

 third molar and the malar process of the superior maxillary bone, the face forms a 

 deep concavity. » 



The orbital surface is a vertical, oblique, and very shallow concavity, sloping 

 upon the malar process outward, downward, and backward. Posteriorly it is defined 

 from the temporal fossa by a superficial ridge hardl}' elevated at the middle, pro- 

 ceeding from the post orbitar process to the outside of the optic foramen. Ante- 

 riorly it is bounded by a general prominence of the face forming a sort of superciliary 

 arch, and by a stout ridge constituted by the lachrymal bone resting upon the com- 

 mencement of the malar process. The orbital surface of the lachrymal bone, 

 presents a small oval foramen, the entrance of the lachrymal canal, which is directed 

 inward, backward, and upward. 



The malar process is directed outward and downward, and the lower part of its 

 root is a short distance above the alveolar margin of the third molar tooth. 



As before stated, the malar bones are broken off and lost from the specimen. In 

 advance of the lachrymal bone the face presents a deep groove, which expands 

 downward and backward uj^on the malar process and the commencement of the 

 malar bone. The upper extremity of this groove has a small foramen opening into 

 it; and about its middle is the exit of the infra-orbital canal, a vertically oval 

 foramen directed forward, and placed about fourteen lines above the alveolar margin. 

 The canal itself is an inch and a half in length, and the entrance to it is situated 

 just posterior to the malar process and an inch and a half above the penultimate 

 molar tooth. 



Si(perior Yieio. — (PI. II.) A striking ditierence in the upper aspect of the skull 

 of Me<jalonijx from that of Jli/lvdon, is the separation of the temporal fossa; by a 

 prominent, pyramidal, sagittal crest instead of a wide intervening surface. The 

 sagittal crest in the specimen under consideration, is cleft by a deep wide fissure 

 with smooth sides, which appears to be the gaping suture of the parietal bones. 

 The tempoi'al sides of the crest are rugged ; and it proceeds at right angles from 

 the marginal ridge of the inion to the frontal bone, upon which it bifurcates into 

 prominent rugged ridges curving forward and outward to the post-orbital pro- 

 tuberances. 



The temporal surfaces are convex and are most rough at their anterior half. 

 Posteriorly, in the vicinity of the temporo-parietal suture and piercing the parietal 

 and temporal bones, there are three venous foramina. 



The face above is smooth and convex, and it does not expand forward as in 



