Vol. XII. 

 1913 



1 Shufeldt, Osteolos^y of Cereopsis novo'-hollandics . 2,\'l 



foramen, and I believe that air gains thorough access to the bone 

 under consideration in Cereopsis, as well as to the major portion 

 of the rest of its skull, including the lower mandible. Hemi-- 

 spherical in form, the facet for the pterygoid of the same side 

 occupies its usual site — that is, just above the mesial mandibular 

 condyle. 



Throughout the Anserince t\\e general character of the quadrate 

 is the same, and in this it closely agrees with the bone as we find 

 it in many of the Aiiatincp and Fiiligulina-. 



Cereopsis possesses a pair of pterygoid bones, fashioned pretty 

 much as we find them in the Anseres generally. Either one of 

 them presents an enlarged anterior end, with a much smaller 

 hinder extremity, the latter bearing the cup-like facet for articula- 

 tion with the quadrate. Between these two extremities the shaft 

 of the bone is somewhat slender, and twisted uj^on itself. Its three 

 borders are inclined to be sharp, and the distal end of the bone 

 is laterally compressed — the interior one }:)assing the entire length 

 of it between the articular ends. On its upper side, distally, there 

 is a large, elongate, sub-elliptical facet for articulation with a 

 similar one on the rostrum of the presphenoid. The major axis 

 of each of these articular facets is placed, for the most part, 

 longitudinally, though, were the imaginary lines produced, they 

 would intersect at a jioint about where the vomer terminates 

 posteriorly. 



At its anterior end, the pterygoid articulates with the hinder 

 extremity of the palatine of the corresponding side. This articula- 

 tion is a pseudo-enarthrosial one — the pterygoid furnishing the 

 " cup " and the palatine the " ball " ; while, above the former, 

 the lip of the pterygoid is produced as a process, as is likewise the 

 lip below. Of these two labia the superior one is always the 

 longer, and here in Cereopsis closely fits into a snug depression 

 intended for it, on the supero-posterior end of the palatine. This 

 is an unusual arrangement, for this superior-distal process of the 

 pterygoid commonly forms an arthrodial articulation with the 

 palatine, gliding upon that part of its surface with which it is in 

 contact. This upper process of the distal end of the pterygoid 

 is very long in Tachyeres cinereus, but short in Branta and in some 

 other Geese. 



The morphology of a palatine bone in the skull of Cereopsis 

 novcB-hollandicB is well shown in fig. 19 of PI. XXXI. of the present 

 paper. Anteriorly, in the case of either of them, the extremity 

 is broad and flat, and considerably compressed from above down- 

 ward. This is placed in the horizontal plane, and a wide interval 

 exists between the two bones. Anteriorly, this is filled in by the 

 fused maxillo-palatines : while, externally, the corresponding 

 maxillary is wedged in — the whole being fused together, and, 

 with the premaxillary and nasals, forming one co-ossified structure. 



Each palatine, for its distal moiety, sends toward the mesial 

 line a broad, curved surface. This is thin, being convex above 

 and correspondingly concave on its basal aspect. Eaclx meets the 



