

KEPT I LI A : VARANOSAURUS 99 



emargination above it, a coracoid fenestra, between the anterior 

 angle of the bone and the angle into which runs the coraco-scapular 

 suture. This emargination reminds one forcibly of the similar 

 emargination or fenestra in many lizards, and is, it seems to me, 

 further proof of the identity of the coracoid in these two groups of 

 animals. At the posterior end the cartilaginous border for the 

 posterior coracoid bone is thickened and rather broad ; it is formed 

 almost equally by the scapula and the anterior coracoid bone; 

 that of the scapula a little larger and more protuberant posteriorly. 

 The thickened preglenoid tuberosity juts outward and backward, 

 and includes between it and the glenoid fossa a little in front a 

 rather large and deep fossa, bounded behind by a rather promi- 

 nent margin formed by the two bones nearly opposite the preglenoid 

 tuberosity of the outer side; in front of this margin and in the 

 narrow fossa formed by it, the subscapular fossa, the supracoracoid 

 foramen opens as usual. 



The absence of a posterior coracoid bone in this genus, as in 

 Seymouria described in the preceding pages, is remarkable. On 

 both sides of the pectoral girdle in this skeleton the humeri lay 

 quite in natural position, indicating its undisturbed condition, but 

 separate ossifications of the posterior coracoids were not preserved. 

 It was not, however, till many other girdles of Varanosaurus had 

 been observed with the scapula quite like the one figured and no 

 remains of separate bones in the place of the posterior coracoids 

 that I became fully assured of their entire absence in this genus; 

 that the non-occurrence was due neither to displacement of separate 

 ossifications nor to juvenility. As it would be absurd to suppose 

 that all the numerous skeletons of Varanosaurus found in this 

 remarkable deposit were juvenile animals of one size or very 

 nearly one size, it is quite certain that Varanosaurus had no ossified 

 posterior coracoid in life. The whole pectoral girdle of Varanosau- 

 rus thus has an almost absolute superficial identity with that of 

 the lizards. Under the usual interpretation, however, the large 

 ossified coracoid of Varanosaurus, with its close resemblance to 

 the coracoid of Varanus, for instance, in its supracoracoid foramen 

 and fenestra, is the procoracoid. In other words, it is assumed 

 that the coracoid of Varanosaurus has disappeared gradually by 



