AND AVES OF NORTH AMERICA. 



225 



In. 



15 



10 

 12 

 14 

 11 



2 

 1 



Length basi-oocipital, 



" sphenoid (oblique), 

 Width of basi-oooipital condyle, 



" between basi-ocoipital processes, 



" <>r sphenoid medially, below, 



" between prooesses of sphenoid, 



" of quadratum antero-externally, 



" " postero- " 



" (greatest) quadratum, condyle, 



" " meatus audilorius, 

 Length quadratum, 



" ramus mandibuli, 



" to splenial joint, 



" to ooronoid process, 



" to cotylus (anterior margin) 

 Width of angle at base, 

 Depth at ooronoid process, 



" " splenial joint, 

 " at twelfth tooth, 

 Length of o. palatinum, 

 Width " " 



Length pterygoid to transverse prooess, 



" transverse process, 

 Width pterygoid at do., 



" " palatine suture, 



Elevation mandibular tooth above dentary, 



" crown only, 5 



Antero-posterior diameter crown do. at base, 8.2 



The lateral processes of the basi-oceipital are ovate, broadly behind, and narrowed anteriorly; they are flat-faced 

 and marked with concentric ruga; on the same; they are connected by a cross-ridge, which forms the boundary of a 

 median obtuse ridge in front of it. The sphenoid is marked by two weak parallel median ridges. Its lateral margins 

 project and are angulate. The anterior processes Cor the pterygoids are flat, and obliquely transverse. The articular 

 faces are directed but little forwards. 



There arc; seventeen teeth on each pterygoid, the posterior smaller and more closely spaced. The anterior tooth 

 is close to the suture with the palatine. The tooth series is everywhere nearer the outer than the inner margin. The 

 palatine suture extends forwards and inwards. Anteriorly the inner margin is more prolonged than the outer, and is 

 connected with it by a concave margin. The! surface of the bone is concave medially and elevated on the inner and 

 outer margins. 



The vomers each have an elevated middle lino, which produces two longitudinal ribs on the median line as in 

 many lacertilians. Their surface is not striate. 



The scapular aroh is only represented by scapula and ooraooid; the other elements, if existing, have been lost. 

 The convex, margin of the ooraooid is vory thin, thickest posteriorly. The outer anterior margin has two angles, one 

 above and one below, the former running out on the plate. 



The two extremities of the humerus are in nearly the same plane, the inferior condyle being directed backwards 

 from it. The head is thick, with superior and inferior tuberosities more prominent than the articular face. The latter 

 is especially huge, aouminate anteriorly, and the bordering portions of the shank coarsely striate. The greater tuber- 

 osity projects posteriorly; its margin is convex. It is separated by a deep groove from the lesser tuberosity, which is 

 equally prominent, but much narrower and more prolonged on the posterior face of the bone. It occupies the summit 

 AMERI. I'll M,(i. Slid. vol,. XIV.— 57 



Lin. 

 18.7 



17 

 I).!) 



17. a 

 io.;s 



18.5 



15 

 !) 

 18.8 



2.4 



18.5 

 8 

 2 

 4 

 4.5 



8 



(i 



10 

 10 



1.1 



(i.4 

 8.5 

 (i 

 12.5 

 5.6 



