1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 313 



iii most birds, and a large pneumatic foramen is seen upon its outer 

 side — a very unusual place for tbis aperture. 



Its mandibular foot is narrow antero-posteriorly and very wide 

 transversely. Two facets occupy its lower surface, separated from eacb 

 other by a concave notch which is deepest anteriorly. 



The bone also presents a smooth articular surface for the quadrato- 

 jugal at the point above mentioned, while a large convex facet is offered 

 to the pterygoidal cup of the corresponding side. 



We find the external opening to the ear to be very small, and hid 

 from sight upon direct lateral view by the quadrate. A sphenotic 

 process is well developed, but the mastoidal one is simply a roughened 

 line; Between the two is a wide crotaphyte valley leading from the 

 fossa of the same name, which is here small, inconspicuous, and entirely 

 lateral. 



The orbital cavity itself is thus seen to be deep aud capacious, lack- 

 ing bony walls principally upon its inferior and anterior aspects. 



Upon its under side this skull presents a number of points of inter- 

 est. The anterior moiety of the superior mandible is here seen to be 

 longitudinally grooved by a broad and shallow furrow, which gradually 

 becomes somewhat narrower as we proceed backward, to finally merge 

 into the convex median portion of the hinder half of this great rostrum. 

 Along its median line it is marked by a few scattered, slit-like fora- 

 mina, that lead into its shallow interior, which latter is largely filled 

 with an cpen mass of spongy, osseous tissue, continuous with the max- 

 illo-palatiues behind. 



The palatine bodies, including their heads, fuse together for their 

 entire extent in the median plane. Resulting from this union we have 

 a single, descending, median carination, composed of the united inner 

 keels of the palatine bodies and a similar superior median oue com- 

 posed of the ascending processes of the same. 



The latter is truncated just before reaching the maxillo-palatine 

 bodies. 



This skull lacks basi pterygoid processes, while the pterygoids them- 

 selves are short, thiek set bones, wilh large anterior and posterior heads, 

 aud sharpened longitudinal crests on the superior aspects of their shafts. 



The basi-temporal triangle is small and its area concave. A thin, 

 pointed lip of bone eaves over the entrance to the Eustachian tubes, 

 which are here apparently thoroughly surrounded by bony walls. 



We find the foramen magnum situated at the bottom of a broad, deep, 

 and transverse concavity. This excavation is bounded on either side 

 by the dome-like mastoid prominences, in front by the line of the base 

 of the basi-temporal triangle, aud behind by a low, smooth ridge which 

 arches between its lateral boundaries. 



The occipital condyle is iather large, ellipsoidal in form, and placed 

 transversely, while the outline of the foramen is also a broad ellipse. 

 but with its long axis placed just the other way. The plane passing 



