206 DESCRIPTION OF A SPECDIEX 



in. 



Length of nasals (in median line, upper surface) 6 



Breadth of the two nasals at posterior end 3.75 



" « « « anterior « 9.5 



Length of beak 100 



" " maxillary (l)y estimate) 112 



Breadth of maxillaries across orbital process (following curve) 71 



" " beak at base 50.5 



" " " one quarter of length from base 3G.5 



" " maxillary at same point 12.75 



" " premaxillary at same point 5.25 



" " beak at middle 28 



" " maxillary at same point 9 



" " premaxillary at same point 4.25 



" " beak at three-quarters length fi-om base 19 



" " maxillary at same point 4 



" " premaxillary at same point 4 



Length of lower jaw in sti-aight line 137.5 



Height at coronoid process 17.375 



" " middle 10 



Amount of curve 15.5 



The proportion of the breadth of the skull to the length is a little more than 46.5 per cent., and that of the 

 beak to the length a little less then 19.5 per cent. 



Occipital Bone. — The various portions are completely coossified. The Basioccipital is 

 pretty smooth and laterally concave. There is no indication of the point where it joins the 

 basisphenoid. Its greatest breadth is 16 1-2 inches. The condyles, which are separated 

 below merely by a slight groove, diverge as they ascend, so that at the point where they 

 cease to bound the foramen magnum they are four inches apart. The length of a condyle 

 along the curve is 13 inches, the greatest breadth 5 3-4 inches. The Exoccipitals, (PI. 

 VI, fig. 2 a), extend backward and outward, joining the squamous in a deep depression in 

 which the posterior portion of the petrous bone lies. There is a rough tuberosity at 

 about the middle of the posterior border of the exoccipital. The supraoccipital is elon- 

 gated, which is one of the characteristics of B. musculus. The distance from the foramen 

 magnum to the apex of this bone (avoiding the crest on the dorsum) is 28 1-2 inches. 

 About eight inches above the foramen magnum a median longitudinal ridge appears, which 

 reaches nearly to the superior angle. At a few inches from its origin it is very promi- 

 nent; above, it gradually subsides. On either side, at about the middle of the lateral 

 edge, over the highest point of the parietals, the bone bulges upward into a greater promi- 

 nence (PI. VI, fig. 1 a) than that of the occipital protuberance. A low, but distinct ridge 

 crosses the middle of the bone transversely through the protuberance, but does not reach the 

 ■edges. A long swelling (PI. vi, fig. 1 b) moreover, passes upward and outward, describing a 

 •curved course from the condyles. It is wortliy of note that this part of the occipital bone 

 is marked by very uncommon prominences, particularly for so young an individual. 



The Squamous Bone. — This bone may be divided into two parts, viz., an inferior oi 

 articular portion (PL vi, fig. 2 b), and a superior or temporal one. The former is, in the main, 

 horizontal, and serves for the articulation of the lower jaw, the latter is, in the main, ver- 

 tical, forming part of the wall of the temporal fossa. 



The articular j^ortion, viewed from below, has the form of an expanded concave plate 



