58 BULLETIN 110, UNITED STATES NATIONAL MUSEUM. 



surface of the gi-eater part of the blade is flattened antero-posteriorly. while the 

 outer surface, excepting the upper fourth is rounded in this direction. The articular 

 end being expanded both antero-posteriorly and transversely is heavy, especially 

 on the posterior half, which has a maximum thickness immediately above the 

 glenoid fossa of 58 mm. The scapula unites with the coracoid by^ a straight 

 suture that bisects the glenoid fossa and is terminated above by a deep notch 

 between the scapula and coracoid on the anterior border. In this individual 

 both scapulae are firmly coossified with their respective coracoids. The scapula 

 of this specimen appears to agree in all particulars with the one found with the 

 mounted skeleton of Antrodemus in the American Museum of Natural History, 

 and it also shows that the limb described by Williston should be referred to 

 this genus. In this connection it is of interest to laiow that the Cerotosaurus scap- 

 ula which formed the basis for the illustration of this bone in the so-called fore limb 

 of AUofiaurus is now in the United States National Museum collections (pi. 26, fig. 

 1). I have recently examined the bone and find that its upper extiemity is 

 incomplete, so that it is not positively known whether this blade has a nonexpanded 

 end as represented by Marsh or whether it was expanded as in Antrodemus. It 

 differs, however, from Antrodemus in having a thinner and wider shaft, and a more 

 abrupt backward curve of the heavy posterior border just above the glenoid fossa. 

 Both inner and outer surfaces of the lower three-fourths of the shaft in Antrodemus 

 are rounded. Both of these specimens came from the famous "Quarry No. 1," near 

 Canon City, Fremont County, Colorado. 



Measurements of scapula of Antrodemus valens. 



( mm. 



Greatest length right scapula and coracoid, measured along cur\e of outside 795 



Greatest length of right scapula •• 652 



Greatest breadth of right scapula 175 



Greatest breadth of blade upper end 145e 



Least breadth of blade 52 



Greatest expanse of glenoid fossa 71 



Coracoid (Cor.). — The coracoid in Antrodemus is quadrangular in outline, this 

 measurement exceeding the antero-posterior diameter. The outer surface is convex 

 in all directions, the inner decidedly concave antero-posteriorly. There is a broad 

 notch on the inferior border. 



The coracoid is pierced by the usual foramen, which runs diagonally through 

 the bone, the external e.xit being larger than the internal. This foramen is entirely 

 inclosed (fig. 40), not a notch as shown in Marsh's figure of the coracoid (pi. 11, fig. 

 1. Dinosaurs of North America). The superior border presents a thin flattened 

 edge, the anterior edge gradually thickening toward the inferior border. 



Measurements of coracoid of Anlrodcmiis valens. 



mm. 



Greatest length at center 120 



Greatest depth at center 170 



Humerus (h). — Comparatively the humerus of Antrodemus is short and some- 

 what sigmoid in form. The shaft is hollow, as are all of the limb and foot bones 

 of this genus. Planes passed through the greatest diameter of the articular ends 

 would cut one another at an angle of 50°. This unusual angulation throws the 



