52 EDWARD A. WILSON. 



On the 19th of January, 1904, at the Cape Royds rookery in lat. 77 45', the 

 moult from the down was in full swing, though not a bird had finished it. For contrast 

 with this, at Cape Adare, some 380 miles further to the north, we saw the same moult 

 in progress on the 9th of January, 1902. This serves to emphasise what has before 

 been noticed, that the more southern rookeries are decidedly later than the northern 

 ones, a fact which one might have expected, because the seasons are relatively far later 

 for a few degrees of southing in those latitudes than in more temperate regions farther 

 north. 



The colour of the feet meanwhile has also been undergoing change. When first 

 the chicks are hatched their feet are very dark, and in the youngest nestling we 

 obtained they were a very dusky blackish red. This rapidly alters for a clear 

 bright red, which reaches its maximum in about three weeks, and then gradually turns 

 to pale flesh colour on the dorsal, and black on the plantar surfaces, and these are 

 retained by the bird for life. The soles of the feet are uniformly black as a rule. It is 

 exceptional that such a piebald mixture of flesh pink and black is seen upon the sole as 

 that figured in fig. 6, Plate X. The colour of the nails is blackish to begin with, 

 but they gradually change in a couple of months to brown. The nails of the adult 

 are long, and brown on the upper surface. Underneath they are darker, and there is a 

 surface marking, which is due, apparently, to the wearing of the nail, the deeper parts 

 of which are of a different density to the surface layers. This surface marking is found 

 in the nails of all the penguins, varying much with the habit of the species, some 

 inhabiting hard, some soft ground, and some at times avoiding all wear by a prolonged 

 stay in the water out at sea. 



Returning now to the change in colouring which takes place at the finish of the 

 first moult when the nestling down is shed, the first noticeable point is that the throat is 

 white. The general colour of the upper part of the head and neck and back is bluish black, 

 with a sharp demarcation line dividing it from the pure white throat, fore-neck, breast 

 and abdomen. The flippers are bluish black above and white beneath, with blackish 

 patches at the tips, which vary much in size and may be absent. The bill in the adult 

 is brick red with black on the tip and upper surface of the upper mandible, while the 

 lower is black upon the sides along the cutting edge. The eyelids in the nestling are 

 black, and become white only at the second autumnal moult. In the immature 

 plumage the suggestion of white eyelids is given at times by the habit the bird has of 

 showing the white sclerotic above the coloured iris ; in the adult this habit enhances 

 the value of the pure white eyelids which are so characteristic. The white ring round 

 the eye which is seen in every photograph of an Adelie Penguin is therefore not due 

 only to the whiteness of the lids. If the bird is watched when neither frightened nor 

 excited the prominence of this white ring is much reduced and the upper lid is almost 

 hidden under the black feathers of the brow. The colour of the iris varies between a 

 warm or almost reddish brown and a brown which has a decided greenish tinge. In 

 one at least of the younger birds the iris was a definite sage green. 



