VERTEBRATA 



97 



wi;^^:^ 



FlGr.36. — Diagrams of the elbow muscles of Icterus [A), showinp the passerine 

 type and NeninaC^)., showing the picarlan type. 6, biceps; emrl, extensor raeticarpi 

 radialis lon^us; h. humerus; s, shoulder; 5r, secondarv remiffes: /, triceps; tpb, 

 tensor patagil brevis; tpi, tensor patagii longus. (After Newton.) 



To the Impennes but one order belongs. This is the 

 Ptilopteri : 



Ilium not anehylosed with sacrum ; bones of 

 wing not foldable on each other; meta- 

 carpals not separated ; hallux directed for- 

 wards ; feathers scale-like ; vertebrte opis- 

 thocoelous ; Ptilopteri. 



The Ptilopteri includes the recent family of Aptenody- 

 tidse or penguins. They first appear in the Upper Eocene 

 of New Zealand. No species, living or extinct, have been 

 found in the Northern Hemisphere. 



