128 Letters, Extracts, Notices, fyc. 



which was presented to the Norwich Museum by Col. Irby, 

 by whom it was shot on 10th November, 1870, differs from 

 other examples that I have seen in having the back of the 

 head and neck very regularly cross-barred with narrow 

 bands of brown, lighter than the brown of other parts of the 

 feather, each feather being for the most part crossed by three 

 such bands. I suspect that this may be an indication of 

 immaturity, though probably one that is subject to consider- 

 able individual variation. 



In a very young bird from Tangier, which had evidently 

 but just left the nest, and which was kindly lent to me by 

 Lord Lilford, there are traces of nuchal markings somewhat 

 similar in character to those on the Spanish specimen at 

 Norwich, but much less regular and conspicuous, and also 

 less sharply defined. 



I may add that in this young bird the light cross-bars on 

 the scapulars are more clearly defined than in the adult, and 

 also that the blackish tint on the face is more extended, 

 nearly surrounding the eyes, and reaching from thence to 

 the edge of the disc. 



Yours &c, 



J. H. GlJRNEY. 



Smithsonian Institution, 



Washington, D.C., 



Nov. 16, 1889. 



Sir, — A letter from Professor Alfred Newton which 

 appeared in ' The Ibis ' of October 1889, having reference 

 to the use to which certain young birds put the terminal 

 claw of their pollux digits, has interested me not a little. 

 Opisthocomus I have never seen, either young or old, in the 

 flesh, but I have seen young Grebes assist themselves in 

 their terrestrial locomotion in precisely the manner which 

 Professor Newton so admirably describes. These, however, 

 are not the only birds that so use their clawed thumbs to 

 assist themselves in their first attempts at progression. So 

 long ago as 1882, in my f Contributions to the Anatomy of 

 Birds/ on page 776, I say that " Mr. James Bell, of Florida, 



