420 Clark, Pterylosis of the Wild Pigeon. [ 0ct . 



pair longest, the outer shortest. Rectrix 1 is inserted almost 

 directly above 2 but the others lie in the same plane. There are 

 six major upper coverts on each side, but 6 is quite small and lies 

 close beside 5 above rectrix 5, while covert 1 though large is pushed 

 outward by the position of rectrix 1 and so lies nearly over rectrix 2. 

 There are six major lower coverts but they lie beneath rectrices 

 2-5 ; covert 1 is largest and covert 6 is smallest. 



The feathering of the lower part of the legs is sparse but con- 

 tinues down on the front of the tarsus 10-12 mm. Posteriorly 

 the feathers do not extend over the joint. 



If the above account of the pterylosis of the Wild Pigeon be 

 compared with the account and figures of the pterylosis of the 

 Columbidse given by Nitzsch, it is evident that Ectopistes has a 

 distinctive arrangement of its feather tracts, of which the most 

 striking character is their tendency to merge with each other. 

 Comparison of the pterylosis of the adult and young Wild Pigeon 

 reveals the highly interesting and important fact that the nearly 

 uniform feather coat of the adult is not a primitive but a secondary 

 condition, just as is known to be the case with the nearly uniform 

 feathering of the ostrich. Perhaps the usual opinion that a uni- 

 form coat of feathers was the original condition from which spe- 

 cialized pterylse have been derived, may prove to be a mistake. 



