244 



Mr. J. W. Hulke. On the Shoulder Girdle 



1888, PI. 75, p. 489 ; and those of Procolophon, described by the same 

 author, 'Phil. Trans.,' B. 1889, p. 255, PL 9, fig. 9. 



Now, the most notable character in the best preserved scapnla 

 figured' by R. Owen (fig. 1, PL 70, op. s. c.), is the large process at the 

 ventral termination of its anterior border separated by a deep notch from 

 the coracoid articular margin of the bone (fig. 6) . This process, though 



Sc 



Pro 



FIG. G. Scapula and precoracoid referred to Dicynodon leoniceps. Owen, 

 ' S. Afric. Kept.,' PI. 70, fig. 1. pre,, precoracoid ; gl., glenoid. 



termed acromion by R. Owen and by Professor H. G. Seeley , can hardly 

 be regarded as homologous with the acromion in higher Yertebrata, 

 since in Dicynodon it articulates with the precoracoid and not with the 

 clavicle (fig. 7). A similar form of the ventral end of the scapula is not 

 infrequent in Anourous Amphibia, but I am not aware that such has 

 yet been demonstrated in the scapula of any Ichthyosaurian. In 

 Dicynodon the clavicles are not known. R. Owen figures (PL 49, 

 fig. 8, op. cit.) a bone associated with a scapula which he considers 

 interclavicle of Kistecephalus. This Professor H. Gr. Seeley inter- 

 prets as clavicle. It is dissociated, and the other ventral constituents 

 of the shoulder girdle are missing. I submit, therefore, that no 

 certain information of the clavicle is derivable from this specimen. 

 In Pareiasaurus, the interclavicle and the clavicles are known, but 

 not the other ventral elements of the girdle, or, at best, most imper- 

 fectly ; nor is the form of the scapula known. In Procolophon, the 

 interclavicle is well shown in the specimen figured by H. Or. Seeley 



