OSTEOLOGY OF BIRDS 



295 



of semiossified ligament. The form of sternum possessed by 

 Netta rufina is practically repeated in the genus Marila, as 

 for example M. americana, M. vallisneria,M. a f - 

 finis, and M . c o 1 1 a r i s , all of which I have examined. 

 In none of them, however, have I ever found the xiphoid notches 

 converted into foramina. We must, as I have already pointed 

 out above, turn to such a genus as Clangula to find this. 



Fig. 26 Pectoral aspect of the sternum of Clangula islandica. Natural 

 size. Drawn by the author from a specimen in his own collection, now in the New 

 York State Museum 



Whether it be the case in Charitonetta albeola I am not 

 prepared to say at this writing, as I have not the sternum of that 

 duck at hand, but I am inclined to believe that it will be found 

 to possess a sternum, as well as many other osteological characters, 

 similar to Clangula. 



H a r e 1 d a liyemalis has a sternum very different from 

 this, and, in so far as my observations go, quite unlike that bone 

 as found in any other American duck. As already stated it reminds 



