230 



STRUCTURE AND CLASSIFICATION OF BIRDS 



in both groups of birds. The sternum in both is unnotched 

 and broader behind than in front. 



In the fore limb the length of the hand distinguishes 



Fin. 105. ANCONAL ASPECT OF LEFT 

 HUMEBUS OF Micropiis melanoleu- 

 cus (AFTER SHUFELDT). 



FIG. 106. PALMAE ASPECT OF SAME 

 BONE (AFTER SHUFELDT). 



both the families of the Macrochires, whence, of course, the 

 name. The nearest approach in length of hand is shown 

 in the swallows, petrels, and, oddly enough, in the penguins. 



FIG. 107. ANCONAL ASPECT OF LEFT 

 HUMERUS OF Trochilus Alexandri 

 (AFTER SHUFELDT). 



p.f, pneumatic fossa. 



FIG. 108 PALMAR ASPECT OF 

 BONE (AFTER SHUFELDT). 



The humerus in both families is extremely short ; the radial 

 crest is well developed in both into a long process which 

 curves over the shaft in the Trochilidae, but over the head in 

 the swifts. 



