126 



REVISION OF THE PELYCOSAURIA. 



meet for more than 3 miti. in the widest part between the ischia, and between the 

 pnbes hardly more than i mm. The bones of the two sides are united through their 

 whole length. The upper part of the ilium is very thin ; the anterior end is rounded, 

 but the posterior end extends backwards as a prominent process with a somewhat 

 thickened lower edge. The anterior and upper edges are thin and fluted with fine 

 grooves. The middle of the internal surface of the ilium is marked by deep and 

 wide pits and by prominent angles showing the attachment of sacral ribs. The 

 whole upper portion of the bone is bent so that the outer face is convex and the inner 

 concave above the acetabulum. The ilium forms the upper third of the acetabulum ; 

 just above the edge of the cavity it is marked by a strong rugosity. On the posterior 

 edge the ilium meets the ischium in a low prominence. The anterior edge is marked 

 by a strong rugosity continuous with the one above the acetabulum. The ilio-pubic 

 suture passes through the middle of this rugosity. The ischium extends posterior to 

 the acetabulum, a distance greater than the antero-posterior width of the acetabulum, 

 100 to 80 mm. The posterior edge is rounded, not drawn to a point, so that the 

 posterior end was blunt and not acuminate. The acetabular border is very prominent, 

 making the cavity ven,- deep at this point. The lower edge is somewhat rounded, 

 but nearly straight, and the suture between the ischium and the pubis is marked by 

 a slight notch. 



The pubis has a thickened upper edge, but the lower portion is abruptly thinned, 

 so that it is not over i or 2 mm. thick. The acetabular edge is raised, but not so 

 much as in the ilium and ischium. Anterior to the acetabulum, the edge of the pubis 

 is somewhat rugose, forming with the ilium a prominent rugosity. The foramen for 

 the internal femoral artery passes obliquely upward and backward from without inward, 

 and the internal opening is much larger than the outer. 



The acetabulum is deep and imperforate. The general outline is triangular, with 

 the characteristic notch on the posterior edge of the iliac portion. There is a promi- 

 nence at each angle on the different bones. These prominences are not connected by 

 raised borders, but are separate, so that the edge of the acetabulum is flush with the 

 bones between the prominences. 



Measuremen/s. — No. 112 University of Chicago. 



Length, bottom line of third cervical, including 



intercentrum 4' 



Anterior face: 



Vertical diameter 34 



Horizontal diameter 4' 



Posterior face: 



Vertical diameter 46 



Horizontal diameter 42 



Height of spine above center of neural canal. 180 



Length, bottom line of fourth cervical 39 



Anterior face; 



Vertical diameter, undistorted 36 



Horizontal diameter, undistorted 36 



Posterior face: 



Vertical diameter 41 



Horizontal diameter 43 



Height of spine above center of neural canal. . 220 



Length, bottom line of an anterior dorsal .... 26 



Anterior face: 



Horizontal diameter, distorted 37 



Vertical diameter, true 42 



Height of complete spine above center of neu- 

 ral canal 860 



Length, bottom line of seventh posterior dor- 

 sal 35 



Anterior face: 



Horizontal diameter (measured %) 32 



Vertical diameter 38 



Posterior face: 



Horizontal diameter 37 



Vertical diameter 33 



Length of spine of gth, nearly 500 



Antero-posterior diameter, base of spine 24 



Transverse diameter, base of spine 7 



Length, bottom line of first lumbar 35 



Anterior face: 



Horizontal diameter, distorted 31 



Vertical diameter 36 



Posterior face: 



Horizontal diameter, true 32 



Vertical diameter, true 32 



Height of spine, twisted, complete 460 



Length, bottom line of posterior lumbar, ap- 

 proximately 24 



Anterior face: 



Horizontal diameter 33 



Vertical diameter 34 



Posterior face: 



Horizontal diameter 30 



Vertical diameter 3° 



Spine, incomplete 322 



complete, about 375 



