OSTEOLOGY OF THE ABMOKED DINOSAUKIA. 



67 



The upper portion of the blade is flattened; about equally expanded fore and 

 aft; upper end cut off at nearly right angles to tbe sbaft, with a slightly thickened 

 rugose border. 



Passing toward the articular end the blade gradually contracts antero-posteri- 

 orly for two-thirds the length of the bone, wliile the tiansverse measurement grad- 

 ually increases. Tlie progressive thickenmg of the bone continues to the articular 

 endjwhich presents a heavy massive surface for the humerus (pi. 2 1, fig. S g). In speci- 

 men No. 7362 this end has .a transverse thickness of 100 mm. and is quite deeply 

 cupped. Approacliing the coracoid end the superior border turns upward at slightly 

 more than a right angle to the blad-e, as in the scapula of Diplodocus (see figure 

 by Hatcher'), forming a broad, thin expansion of tliis end. No acroiuian process 

 is present. 



Two of the seven scapulae in the National Museum (Nos. 4934 and 7361) are 

 fii'mly coossified with the coracoid, forming with it a deep glenoid cavity of good 

 size. Tliis fossa in No. 7361 measures 165 mm. across fi-om lip to lip, its greatest 



expanse. 



Measurements of scapulae. 





S. slenops 



No. 4934, 

 left. 



Stegosau- 

 TUS sp. 



No. 7362, 

 right. 



Stegosaw- 

 rua sp. 



No. 7361, 

 right. 



5. stenops. 



No. 7371, 



left. 



S. sterwps. 



No. 4929, 



left. 





620 



226 

 384 



670 

 1215 



mm. 

 685 



67!) 

 192 



7Bm. 

 687 



215 



Greatest breadth, proximal 



Greatest breadth, distal end. . . 



380 

 140 



138 



110 



135 







Coracoid. — The coracoitl is a subquadrate bone (pi. 20, fig. 1) which in very old 

 mdividuals becomes fu-mly coossified with the scapula. The superior portion of 

 the coracoid is thin, with convex external and concave internal surfaces. The lower 

 portion is much thickened, particularly that part contributing to the glenoid fossa, 

 which in No. 7376 measures 163 mm. in transverse width. The anterior portion of 

 the inferior border is considerably thickened and roughenerl fcu" ligamentary attach- 

 ment. ^ 



The coracoid foramen is large and its elliptical internal opening is situated just 

 anterior to the coraco-scapula suture, contmuing diagonally forward through the 

 coracoid a little below the center of the bone. There are five coracoids in the col- 

 lection, and all of them show this foramen to be entirely mclosed, and not a notch, 

 as figured by Mai-sh in his illustrations of this element of Stegosaurus ungulatus. 



1 Mem. Carnegie Mus., vol. 1, p. 44, fig. 14, 1901. 



