THE BIRDS OF THE PRIBILOF ISLANDS. 



376 



On the lower portion of the legs of my larger young specimen there are quite a 

 number of feathers nearly full grown, which in their appearance differ greatly from 

 tl^ose on the body. Their distal outline, instead of being clean cut, have the rami 

 considerably lengthened and fluffy. At first glance this would seem to be similar to 

 the down attached to the first feathers of other birds, but under the microscope it is 

 seen that the rami tips are simply lengthened, they having longer radii than usual. 

 They are really partially semiplumaceous feathers. But attached to the tips of one 

 or two of the rami on nearly every one of these feathers is a slight swelling with a 

 continuation of the rami at its apex. These ends are variously broken and imperfect, 

 but there can be no question but that they are a relic of the first down growth, and 

 hence are identical with those described under Tringa ptilocnemis, but of course greatly 

 degenerate. Also on the early upper tail coverts the tips carry a rudiment of the 

 down growth. 



In the higher groups, according to the position of the birds in the avian scale and 

 the flight and nidiflcatiou characteristics, the suppression of the first downs on the 



f 9 K 



Tips of Feathers of Touhg Cokmorant. 

 a b, c, d, e, from lower portion of leg, showing variously worn rami tips, d and e wit^ rudiments of down attached ; 

 /, tip of a secondary, the upper portion being the degenerate down ; g, tip of an upper tail covert^ with rudimentary down 

 attached; ft, tip of a tertial with a more perfect though rudimentary down. All greatly enlarged. 



tips of the flight feathers is either complete or partially so. In the birds of this order 

 there is a slight differeuce according to the family, but as a rule the down is persistent 

 on a small portion of the growing flight feather. In the cormorant it is much less so 

 than in the other examples of the order that I have seen. On some secondaries and 

 tertiaries of the larger of my young specimens there are attached to the tips a pro- 

 longation of the rachis, having longer rami but shorter radii than those immediately 

 below. A very similar though more perfect structure is found in some other birds of 

 other orders, where there can be no question as to their downy nature and position. 

 Unquestionably this irregular, imperfect, and short-lived growth is the remnant of 

 the downs of the flight feathers. They rarely exceed 3 or 4 millimeters in length. 

 In Sula they are much larger and more persistent, and differ but little in the other 



families. 



Unlike most water birds, the cormorant is hatched nude and its eggs are very 

 small, considering the bulk of the parents. Soon after hatching the down appears, 

 short at first but increasing in length as the bird grows. As it reaches fujl size the 



