2 TASSERIFORMEH. 



feather about to be developed ; it is of a fragile and light nature, 

 not easily observed, and does not hide the skin. The chicks 

 themselves are helpless, cannot walk, and, until they are full-grown 

 and have acquired the faculty of flight, they are brought up by 

 the parent birds in a nest, constructed with some skill by the 

 latter, and have the food placed in their mouths by the parent 

 birds." {Of. Nicholson's translation, p. 43, 1889.)] 



It may here be noted that the subject has never been fully 

 worked out, for the nestling of the Shore-Lark (Otocori/s alpestris), 

 when hatched, is hidden by yellow down ; but this is arranged 

 in tufts, and on examination is very different from the close-set 

 down of a nestling Hawk or Owl, where it entirely covers the body. 

 Another Passerine bird which shows downy tufts adhering to the 

 apes of the true plume is Ptihcliloris hucllcyi, from Ecuador (cf. 

 Scl. & Salv. P. Z. S. 1880, p. 158, pi. xvi. ; Scl. Cat. B. Brit. Mus. 

 xiv. p. 318, 1888). 



Probably all the genera of Passeriformes pass through a more or 

 less downy stage ; but I think that the character of the downy 

 plumage will be found in every ease to be different in complexion 

 and development from the downy young of the Dasijpcedes, though 

 Meiiura appears to he an exception, and 1 have recently separated 

 it from the other Passeres. 



B. A spinal feather-tract on a considerable part of the neck, 

 well defined hy lateral bare tracts and not split by a S])inal 



bare tract. 



Fm. 1. 



lit 





te 





fill 



WMm 



Doisril view of Turdua vmdcus, to show the pterylosis of a typical Passe- 

 rine Bird. (From a specimen in the Index Series in the Natural 

 Ilistorv Museum, by permission of Professor Flower, C.B., F.B.8.) 



