OOLOGY. 



15 



ers of the otherwise white under parts ; whence I infer that m very young 

 birds the whole under parts may be brownish or grayish." 



In the more advanced of the two specimens preserved (original No. 62), 

 the entire body is as black as a crow. On the breast, however, and 

 under parts generally, the bases of the feathers show wliite to near the 

 ends, while upon the crissum and about the head they are grayish. The 

 surmise of Dr. Coues, therefore, with regard to the young plumage, was 

 in the right direction, but did not go far enough. The indications of an 

 adult white and gray plumage are unmistakable. 



The very young birds first found were completely covered, as is usual 

 in the family, with slate-colored down. The same covering is plentiful 

 upon the younger of the two specimens preserved (original No. 66), 

 and still distinct upon the elder. 



Below are contrasted three sets of measurements, viz : those of adult 

 skins by Dr. Coues, and the young of the same from recent specimens 

 by Dr. Kidder: — 



It should be noted that the measurements of tail, bill, head, tarsus, 

 middle toe, and claw of the last specimen were taken from the skin, and 

 are therefore not " recent." 



(ESTRELATA KIDDERI, CoU€S. (p. 28.) 



Nests in deep burrows excavated in a hill side, each burrow containing 

 a little pool of fresh water near its entrance. Egg is single, dull white, 

 and very obtusely ovoid in shape, almost as globose as a Penguin's egg', 

 first found October 11. Shell is thin, brittle, of compact structure, and 

 marked externally by very shallow linear depressions, discernible only 

 by aid of a lens. There are no color-markings. 



The measurements are as follows : — 



