1916] Chandler: Structure of Feathers 391 
Passeriformes 
Accipitres 
Eurypygidae 
Cathartae 
Psophiidae 
| Galliformes 
Crypturiformes 
Rallidae 
Procellartiformes 
Phaéthontidae 
Colymbiformes 
Casuariiformes 
Apterygiformes 
Sphenisciformes 
Archaeopteryx Struthioniformes 
Fig. G. Phylogenetic tree showing hypothetical relationships of birds, based 
on Knowlton and Ridgway’s (1909) classification, with all changes 
suggested by morphology of feathers incorporated. 
