PTERYLOSIS 17 



apivora, Coracias garrulus, Bhamphastos, Musophaga, Gal- 

 lus, various cuckoos, Gharadrius, &c. They do not divide 

 in Pandion, Gypselus, Cuculus, Opisthocomus, Buceros, Go- 

 lumba, Fulica, and Giconia. ; 



Gareod made originally the apparently reasonable sug- 

 gestion that the down feathers upon the apteria of many 

 birds may be the remains of contour feathers, from which 

 |» the inference is necessary that those birds with downs upon 

 the apteria are nearer to the continuously feathered and 

 ancestral bird than are those whose apteria are nude. But 

 the whole matter is rather more complicated than this. 

 There are birds with only contour feathers and nude apteria ; 

 there are birds with contour feathers only upon the pterylse, 

 and down upon the apteria ; there are birds with downs 

 everywhere ; and finally there are birds with downs only 

 upon the pterylae, mixed with the contour feathers. The 

 facts, therefore, when stated thus fully are not so easy of 

 interpretation. 



The evidence derivable from Archaopieryx — less negative, 

 perhaps, than ' negative ' evidence often is — may afford us a 

 clue. So many feathers of that bird are well preserved that 

 it seems possible that where feathers have not been preserved 

 they were either really absent or soft down feathers. The 

 latter suggestion seems to be the more probable, on account 

 of the plain fact that Archmopteryx was a flying bird. Now 

 the fact that the contour feathers are frequently preceded 

 by downs points in the same direction, viz. that the primitive 

 feathering of birds was in the form of downs. The persist- 

 ence of downs, therefore, on this hypothesis is so far a 

 primitive character, and the greater the persistence the more 

 primitive the bird. Thus those birds which have downs 

 everywhere will be the more archaic. This is so far promis- 

 ing that that group contains such apparently old types as 

 P'alamedea, Opisthocomus, BMnochetus, &c. On this view 

 the most modern of birds will be those which I elsewhere 

 try to show are an ancient race, i.e. the bulk of the Pico- 

 Pstsseres. But, as might be expected with an ancient race, 

 there is every variety shown, and members of this great 



c 



