W. P. PYCR AFT : BLACK-THROATED DIVER. 97 



scapula is a vestige of the dorsal extension of this space. 

 (Fig. 2.) 



miiu 



FIG. 2. 

 PTERYLOSIS OF THE BLACK-THROATED DIVER (UPPERSIDE). 



[The dotted areas represent the pterylce or feather-tracts. 



The cervical tract is absolutely continuous. The spinal 

 tract is of enormous width posteriorly, and blends with 

 the femoral tract, which is unusually closely feathered. 



