654 PROCEEDINGS OP THE NATIONAL MUSEUM. vol. 45. 



gradually to the apex, without the convexity at the middle of its 

 length which is characteristic of M. europseus. In the basal half of 

 the beak the upper surface of the maxillae is horizontal, but in the 

 distal half beveled, or inclined outward. Internal free borders of 

 premaxillae widely separated opposite the base of the beak, more 

 closely approximated anteriorly, but again diverging at the apex. 

 The mesirostral bone occupies the proximal two-thirds of the vomer- 

 ine trough. It is depressed below the upper surface of the premax- 

 illse and divided unsymmetrically into two flat portions the surfaces 

 of which are inclined toward each other. 



Lateral aspect. — Outline of occipital moderately convex. Con- 

 dyles strongly projecting. Superior border of frontal plates of max- 

 illae nearly horizontal and nearly as long as the temporal fossae. The 

 latter pyriform, with the superior border only moderately concave. 



Fig. 1.— Posterior aspect of skull. 



External angle of the exoccipital, which articulates with the zygo- 

 matic, truncated. Zygomatic processes large, thick, and truncated 

 both anteriorly and posteriorly. The postglenoid process large and 

 strongly projecting. Orbit large, with the superior border slightly 

 convex. Free margin of the lachrymal nearly one-half as long as 

 the orbit. Maxillary prominences high and angular, appearing as if 

 truncated anteriorly. Lateral free border of rostrum curved upward 

 at the proximal end. 



Pterygoids large and strongly projecting outward and downward. 

 The posterior notch longer and narrower than in M. europseus. Infe- 

 rior outline of the rostrum straight, continuous at the base with that 

 of the pterygoids. In M. europseus the inferior outline is convex and 

 cut off at the base by that of the pterygoids, which meets it at an 

 angle. 



