1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 275 



narium in the median plaue. This arrangement is exactly what we 

 found in some of the Auks, though, of course, modeled to accommodate 

 itself to the differently proportioned parts, and the nasal septum is also 

 absent in the latter. 



The cranio-facial hinge, then, in the Albatross is a very free one, 

 though not so much so as we find it in Sula. 



A direct basal view (Fig. 14) of the skull of Diomedea albatrus pre- 

 sents us from before backward the following points for examination: 

 (1) The anterior half of the superior mandible is canoe-shaped, the 

 prominent hook taking the place of the prow. (2) The largely de- 

 veloped palatines are considerably below the maxillojugal bars; an- 

 teriorly they are carried forward as prominent and parallel ridges with- 

 in the dentary borders of the premaxillary to subside on the inner sides 

 of the canoe-shaped portion beyond. (3) The postero external angles of 

 the palatines are rounded, the "external lainime" being sharp, while 

 the "internal lamina'" are thickened and rather conspicuous cariua- 

 tions. (4) Between these latter an oval interspace occurs, which is 

 carried forward as a deep median cleft as far as, or rather farther than, 

 the point where the anterior ridges of the palatines described above 

 subside upon the sides of the premaxillary. (5) At about the middle 

 point in this cleft a small oval plate of bone makes its appearance; this 

 is the foot of the anterior end of the large decurved vomer of this Alba- 

 tross. (6) A short distance posterior to this appear two slit-like marks, 

 one on either side, their free ends being behind and close to the pala- 

 tine bones; these are the inferior arcs of the inaxillo-palatines. (7) The 

 pterygoids are strong, straight bones, their lower aspects being rounded, 

 their upper ones longitudinally sharp-crested; their heads and the pala- 

 tine heads all meet to form upon their upper side a deep groove for the 

 rostrum. (8) A considerable portion of this latter may be seen between 

 this articulation and the basi-temporal region in the median line. (9) The 

 Eustachian tubes are open, naked grooves. (10) The basi-temporal 

 triangular area is quite as much contracted as we find it in Sula or 

 Pelecanus. (11) The condyle is rather elevated and transversely ellip- 

 tical. (12) The foramen magnum is large, broadly elliptical, with its 

 major axis, like Pelecanus and Sula, in the median line. It is at the 

 base of a notable convexity which occupies all the area posterior to the 

 basi-temporal region and extending from side to side between the mas- 

 toidal prominence. 



The periphery of the foramen magnum lies iu a plane which makes an 

 angle of 45 degrees with the plane of the basis cranii. 



In addition to these principal characters, we must also notice that the 

 inner facets on the mandibular feet of the quadrates are the lower, aud 

 are about in the same plane with the lower margins of the internal 

 laminse of the palatines. 



Returning for the moment to these latter bones, we find that their 

 "ascending processes" are lofty and handsomely cm led about the an- 



