1914] Beebe: Ontogeny of the White Ibis. 243 



brachium or fore-arm are covered with a dense growth of down, 

 jet black on the crown where it is sleek and velvety, but becom- 

 ing somewhat longer and of a brownish, smoky hue on the neck 

 and wings. The remainder of the body is at first almost bare 

 and later only thinly clad with straggling, woolly down, smoky 

 gray on the dorsal surface and white on the under parts. It 

 would seem as if the young bird was prepared for protection 

 from the cold only on the head and neck, somewhat as in the 

 emperor penguin, in which these portions project from the der- 

 mal pouch of the parents. 



The crown down consists of a spray of 10 or 12 spine-like 

 barbs, of equal length (about 6 mm.), furnished with simple 

 barbules along their basal half. A down feather from the back 

 has usually a greater number of barbs, considerably longer 

 (15 mm.), whitish at the base, shading into smoky gray, very 

 soft and pliable and clothed almost to the tip with barbules of 

 similar texture. These two types of down characterize the two 

 distinct zones which I have mentioned. The egg-tooth is small 

 but very sharp, white and fixed on a dusky rectangular base 

 which is shed about the third day. The wing claws are small, 

 with sharp, recurved tips and are present on the first and sec- 

 ond digits. The legs and feet are large and strong. All the 

 visible skin of the body and the anterior aspect of the tarsus is 

 of a dull leaden hue, the posterior tarsus and the feet being flesh 

 colored. The curious changes in the flesh colors of the face and 

 bill and the iris I will describe separately. 



Although at the time of hatching the down of the head and 

 neck is more advanced than that of the body in general, yet the 

 changes which take place during the ensuing two or three weeks 

 reverse this condition. The contour feathers of the body and 

 wings sprout at once while the head and neck remain as at birth. 

 During the third week when the sheaths have begun to dry up 

 and the juvenile plumage becomes recognizable, the young bird 

 becomes restless and now and then climbs out of the nest and 

 along the nearby branches. When a month old, if frightened it 

 will fall or scramble to the ground, but when this happens in the 

 flying cage the young Ibis is not able to return in spite of its 

 excellent climbing powers, but must be replaced by the keeper. 



