200 
FRANCIS H. HERRICK 
must be considered in relation to all the other special instincts 
and adjustments, in consequence of which these cuckoos have 
become as completely adapted to the conditions of their life as 
have the young of any New or Old World species 
The human infant is credited with the ability of sustaining its 
own weight with its arms, but as we have seen, the infant cuckoo 
can not only sustain its weight with one or both limbs or by a 
single toe for an extraordinary length of time, but shortly can 
perform the remarkable feat of drawing itself up with the muscular 
power of one leg. 
B. The food-reaction and its modification through 
association 
The food-response, which has the nature of a chain-reflex, is 
a complicated act, in the course of which the head is elevated, and 
the mouth opened wide, revealing in this species a dull red mouth 
cavity, marked in a highly peculiar manner. A series of sym- 
metrically arranged snow white spots or pads, converge about the 
glottis and internal nares, some 14 in number, nearly all with the 
exception of a prominent spot on the tongue being confined to 
the palate, (figs, a and 5) the whole presenting a very peculiar 
appearance, and suggesting the ornamented throat of the nestling 
of the Gouldian weaver finch (Poephila gouldiae) from Australia, 
figured by Sharped' but without colored wattles on the gape. 
This complex performance, which represents the simplest sign- 
language of the hungry bird, appears as a uniform chain-reflex, 
and is as predictable, and seems to be as mechanical as the re- 
sponse of an electric bell. It does not, however, long remain 
in this unmodified state. Though at first called into play, so 
far as can be ascertained by an external stimulus alone, as by jar- 
ring, sound, and possibly by the action of the air, and as often as 
any stimulus acts, within the limits of fatigue, from the moment 
of birth this reaction becomes modified intermittently (a) by 
hunger, and steadily (h) by association with the parent and nor- 
. « Op. ext., p. 116. 
