26 EDWARD A. WILSON. 
in this case be tending to whiteness would be either of the extremes of temperature, 
and should be better exemplified by Polar and Tropical species than by those of 
Temperate regions. One other suggestion I would make, namely, that it is an economy 
to a bird or beast to produce white or unpigmented feather or hair, when such feather 
or hair has not necessarily got to stand much wear and tear. White feathers 
undoubtedly wear out far more quickly than pigmented feathers; as, for example, in 
the moulted primaries of our common Herring Gull (Larus argentatus), where the result 
of wear and tear on pigmented and unpigmented parts of the same feather may readily 
be seen, and perhaps even better still in the feathers of the Curlew (Numenius 
arquatus) (fig. 46, p. 104). 
With the hope of throwing light on the rate of growth of the young Emperor 
Penguin chickens, we took two on September 13th, 1903, the largest we could find 
in the rookery, back to the ship. 
On September 20th these weighed respectively 636 and 6623 grms. The less 
heavy of the two, which survived until December 10th, increased at the following 
rate :— 
September 38rd, 1903, probable date of hatching, probable weight 450 grms. 
oy, (UGlirGt: “aus «ae ae coe see ee cee oe 
on! GEE’, wet. «GC. «OS. 6 ee Se 
October 4th es sas a ai ahi side we 124755, 
pe Auli: wee i, «ea ttt 
ie, SABE eae eet ae, ee 
= OG, we ee oe, a | ae | a, Sh 
November lst... .. over 2000 
(Nore.—453 grms. = 1 lb.) 
We weighed also several others taken on different dates, for example :— 
No. 16. Immature in down, found dead. Sept. 13, 1903 .. Weighed 453 grms 
No. 1. > e taken alive. Oct. 18, 1908 a re 1698°75 ,, 
No. 2. 5 és taken alive. Oct. 18, 1903 an as 1812 a5 
No. 3. 53 5 found dead. Nov. 2, 1903 i * 1670°4 ,, 
No. 4. 43 - taken alive. Nov. 5, 1903 Pn 55 1245°75 ,, 
The weight of a large egg (No. 34), slightly incubated, was just short of 1 lb. 
(448°5 grms.). 
Probably for the first month or two of its life each chicken puts on rather more 
than half a pound per week, but in its third and fourth months this average must be 
largely increased, for in January the chick reaches a bulk equal to about half that of 
an adult bird, and probably weighs as much as 30 lbs. 
The voice of the chick is a very shrill rattling pipe or whistle when it is hungry. 
First it lowers its head to the ground, craning the neck to its full extent, and then 
suddenly swings it up as far as it will go, rattling out a very shrill piercing whistle of 
four notes. It is a crescendo pipe, rising in pitch and in shrillness and suddenly 
dropping at the end note. Out on the ice in the open air the rookery sounds as though 
it were full of farmyard chickens. In a confined cabin the noise, even of two 
