248 ZOOLOGY. 



differ widely in many respects from the ordinary organiza- 

 tion, and in none more than what concerns the structure of 

 the shoulder ; we allude to the ornithorhynchus paradoxus 

 and echidna setosa, of New Holland. In these the skeleton 

 of the shoulder more resembles what we find in lizards and 

 in birds than in mammals.* 



Fig. 213. The Roe, or Roebuck ; .Chevreuil. 



The function of the basilar portion of the skeleton of the 

 abdominal or hinder limbs varies less thau does that of the 

 pectoral. In the cetacea, also in the dugbng and lamantin, 

 the pelvis is reduced to a mere fragment; in other mammals, 



* The arrangement of the bones of the shoulder in these singular animals 

 will be best understood by a reference to Fig. 211, in which d points to two 

 bones on each side (of which one is not represented here) corresponding to 

 the usual collar bones of mammals; a points to the scapula ; h to the cavity 

 for the articulation of the head of the humerus; o the prolongation of the 

 scapula to the sternum, analogous to the coracoid clavicle of birds ; co an 

 osseous piece, the analogue of which has not been determined ; s and c point 

 to the ribs. The meaning of this complexity of the shoulder in this class of 

 animals has never yet been explained. R. K. 



