214 



Hans Gadow: 



well-known in- and evaginated follicle. It was E. B. Poulton 

 who first pointed out that the feather follicle itself is merely a 

 mechanism whereby a better „nutrition and support" of the 

 feather is attained.^) 



Epid. 



Cutis. 



Fig. 1. 



Fig. 2. 



Fig. 3. 



Conc. 



Fig. 4. 



Epitricli 



Sheath 



Feather 



Spool 



Fig. :. 



Fig. 6. 



Fig. 7. 



Scheines illustrating the origiii of Feathers. 



1. A Scale with epidermal thickening at the apex. 



2. Thickening with incipient pulpa. 



3. Papilla „rising" above the surface level of the original scales 

 area, the scale having last its ,,body" excepting so far as 

 this is represented by the pulpa. 



1) This sentence is quoted from O. Riddle, „Genesis of Fault-bars 

 . . . "who refers to Professor Poulton's Structiire of the bill and hair of 

 Ornithorhynchus, Q. J. M. S. June 1894. 



