VII.] 



MONOTREMATA. 



The T-shaped bone, interclavicle or episternum. (if) in front 

 of the presternum, which connects it with the clavicle 

 and is often completely fused with it, appears to have 



FIG. 44. Sternum and adjacent parts of the skeleton of a young Ornithorhynchus 

 (l). anatini4i) ( clavicle ; if interclavicle ; fx> pro osteon (a part of the true 

 kternum) ; fs prcstcrnum ; nis mcsostcrnum ; sr sternal ribs ; ir intermediate ribs ; 

 vr vertebral nbs. 



no homologue among the other Mammalia, and belongs 

 more properly to the shoulder-girdle than to the sternal 

 apparatus. 



