Type of the Genus Massospondylus. 109 



and has a subquadrate form. The articulation for the pubis 

 is semicircular, 2^ inches wide and 1 inch long, the convexity- 

 being in front. 



The Ischium. (Fig. 5.) 



There are several examples of ischium — nos. 349, 350, 357, 

 and 359 ; the last was identified by Sir R. Owen as the body of 

 the left ischium. There is no certain evidence of the length 

 of the bone, though its form and general characters are 

 obvious. I regard the specimen 349-50 (fig. 5) as having been 

 a foot long, and believe that it was articulated obliquely to 

 the ilium. Its proximal end is concave on the posterior border 

 and becomes straight distally ; its anterior border is divided into 

 two parts by a tuberosity near the proximal end, which was 

 directed inward. This tuberosity has the form of the anterior 



Fig. 5. 



Acetabular surface ^i=— ^7"^ 



Pubic process. 



Posterior margin 



Restoration of the ischium based upon two fragments, ^ nat. size. 



acromial crest of a scapula, and makes the anterior outline of 

 the length of the bone concave. The proximal anterior 

 margin above the tuberosity is thin and fractured. Thus the 

 ischium is nearly 3 inches wide at the proximal extremity ; 

 1^ inch of the surface is for articulation with the ilium, and 

 the anterior smooth concave part is a portion of the acetabular 

 border. The width at the tuberosity is a little greater and at 

 the posterior fracture the bone is 2 inches wide. The distal 

 extremity of no. 350 must have been more than 3 inches 

 wide, and terminated in a flat oblique cartilaginous surface. 

 If that be taken as indicating the horizontal base of the bone^ 



