Mr. R. F. Tomes on White's Thrush. 387 



even more so than in that species. The lateral notches enter into 

 the boue for half its length, and are proportionally broad; while 

 the side processes are so short that their outer angle reaches 

 scarcely further in a forward direction than two-thirds of the 

 entire length of the sternum, taken along the line of the keel. 



Wishing, if possible, to ascertain moi-e exactly the impoi*tance 

 of this character, and knowing that the adult plumage of 07-eo- 

 cincla represents the immature plumage of some of the more 

 typical Thrushes, I obtained for examination some of the latter 

 when in that stage of plumage which most nearly resembles that 

 of the Oreocincla. The results were satisfactory. I select as 

 an example the Missel-thrush. In a mature bird the hinder 

 margin of the sternum is transverse and but slightly rounded, — 

 the notches on either side being of moderate size, and almost 

 closed posteriorly. In a young bird, full-grown but retaining the 

 spotted nesting-plumage, the hinder margin of the sternum is 

 more rounded, and its lateral incisions are deep and open — in 

 a word, very much like that part of the sternum of the 0?'eo- 

 cincla aurea. The same differences in the sternum at different 

 ages obtain also in the Ring -ousel, probably also in many other 

 species. 



Through the great kindness of Mr. Alfred Newton I am 

 enabled to add a few notes on the sternum of some other 

 Turdid(B : — 



1. Turdus migratorius. — Form typical, sternum indicating a 

 state of development similar to those of the Fieldfare and Ring- 

 ousel. 



2. T. fuscatus, Vieill. West Indies. — Two sterna of this 

 species, sent by Mr. Newton, diflFer somewhat in the size and 

 openness of the notch in the hinder part, but in both they are 

 of moderate size. In one they are very like those in the ster- 

 num of the adult Missel-thrush ; but in the other they are so 

 much closed posteriorly as to present the appearance of two oval 

 foramina. In general outline, too, the sternum of this species 

 and the Missel-thrush bear considerable resemblance to each 

 other. 



3. Monticola cyanea. — The first thing noticeable in the sternum 

 of this species is its small size compared with that of the Redwing 



2e.2 



