144 SHUFELDT. [Vol. XVII. 



posterior to the orbital cavities. The beak is comparatively 

 feebly developed, being powerfully deflected from the frontal 

 region, obliquely downward, in addition to being quite short. 

 The mandibles, omitting their horny sheath, and measured from 

 the frontal bones, will enter almost 2.2 times into the total 

 length of the cranium. The cranium's superior surface ex- 

 hibits a median furrow that is especially well marked in the 

 frontal region, posterior to the supraorbital processes. 



The orbital cavities are relatively small, due to the fact that 

 their posterior borders, where formed by the frontal bones, are 

 obliquely truncated ; and, moreover, the alisphenoids are short 

 and thick. The osseous crest of the alisphenoid {proc. orbit, 

 poster^, as we pass upwards, is seen to become rapidly nar- 

 rower, it having its greatest width about its center ; upon the 

 broadest portion there is, on the external border, a process 

 directed backwards and outwards, and which affords attach- 

 ment for the superior portion of the tensor muscle that passes 

 to the ear-flaps. This process is symmetrical upon either side, 

 although the muscle referred to is asymmetrical at its distal 

 extremity. The frontal region is comparatively narrow, partic- 

 ularly so posterior to the supraorbital processes, where, indeed, 

 it is narrower than is the part in front of them ; while the 

 orbital borders are nearly parallel to each other. The frontal 

 bones of the posterior orbital peripheries slope obliquely away, 

 being abruptly truncated above and below, and have a height 

 that is somewhat less than the length of a pterygoid bone. 

 Inasmuch as both the alisphenoid and mesethmoid are thick- 

 ened bones, the interorbital septum is necessarily so, the only 

 exception to this being a place just above the sphenoidal ros- 

 trum, where the septum is seen to be thin (semitransparent). 



The osseous crest of the os squamosmn is not especially well 

 individualized superiorly (by an evident and deep groove sepa- 

 rating it from the alisphenoid), but is continuous in the upward 

 direction without any intervening cleft, or glenoid fossa, quite 

 up to the frontal ; as the crest thus becomes somewhat long, 

 and is likewise rather deep, and possesses a semi-anteriorly 

 directed border, it forms a fossa, opening anteriorly, which is 

 larger than the similar cavity seen in the other species having 



