the Shoulder-girdle of a Plesiosaur. 



343 



Altliough the elements of this pectoral arch are free from 

 matrix, and in no way united with one another, there can be 

 little doubt that the figure represents very nearly their rela- 

 tive position during life. In the first place, the fact that the 

 clavicles met in the middle line is shown by the structure of 



Fio-. 4. 



/'V 



I 



\ 



\ 



V 



Complete shoulder-girdle of a young specimen of Cnjptuclidm oxoniensis 

 (Leeds Coll. 86). About \ nat. size. 



their median border ; in the next, the position of the outer 

 ends of the clavicles with regard to the scapulae is settled by 

 the depression on the anterior border of those bones into 

 which the outer part of the hinder edge of the clavicle fits, 



