1888.1 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 311 



space anterior to the rhinal chamber. They unite in the median line, 

 are bounded above by the prernaxillary, below by the united palatines, 

 while the anterior extremity of the maxillary fuses with the mass at 

 about its middle on either side. 



In form this maxillopalatine mass is wedge-shaped, with the broad 

 end anchylosed with the under side of the united nasal processes of the 

 premaxillary. 



Posteriorly its wall is composed of compact tissue, being at right 

 angles to the longitudinal axis of the skull. It slants from the under 

 side of the cranio facial hinge to the anterior margin of a median fora- 

 men, seen just anterior to the keel which is formed by the union of the 

 palatines behind. 



This posterior maxillo-palatiue wall has a cleft in its lower two thirds, 

 while two conical pits, placed side by side, lined with compact osseous 

 tissue, occupy its npper third. They have their bases opening in the 

 rhinal chamber, and their apices are pierced by the small subcircular 

 nostrils, one in each conical passage. 



The hinder half of the jugal bar is compressed from side to side, 

 slightly dilated, with its end crooked up, and in life simply bound to 

 the upper and outer side of the quadrate. 



The body of a lachrymal fuses completely with the cranial elements 

 above, its upper surface assisting in forming the smooth superfices of 

 the frontal region. From this portion it semis downward and slightly 

 backward a descending process. This is composed of a cylindrical ped- 

 icel for its upper third and an antero-posteriorly compressed portion 

 for the lower two thirds. It fails to reach the maxillary, its tip remain- 

 ing free just above that perpendicularly compressed bar which passes 

 immediately beneath it. 



The interorbital septum is entire, with the exception of a semicircu- 

 lar perforation, which is immediately in front of the aperture in the 

 anterior wall of the brain case that gives egress to the optic nerves. 



Each olfactory has a small foramen in either orbit at its usual site; 

 the track for the nerve being a broad, shallow groove beneath the or- 

 bital vault. 



Tbc mescthmoid is very deep; its anterior border is sharp and thin. 

 Commencing in the aperture of the angle between the pterygoidal shafts, 

 it is carried directly upward and forward to the expanded portion be- 

 neath the roof of the crauio-facial region, the edge meeting the median 

 division of the ruaxillo palatines (Fig. I<>). 



The lower fourth of this ethmoidal border is thickened and rounded 

 for the articulation of the palatine and pterygoidal heads. 



Coming, as usual, from the anterior apex of the basi temporal tri- 

 angle, the other portion of the rostrum is decurved and meets the point 

 referred to above in the angle between the pterygoids. 



A quadrate is a very large bone with a broad, triangular orbital proc- 

 ess. Its mastoidal head can hardly be said to be divided into two, as 



