G.U.LIXACEOUS BIRDS. 
89 
pressed, ami the feathers feel liard and firm to the 
touch, from the thickness and strength of the rachls 
or shaft. Upon the neck they assume a variety of 
forms, in some species being rounded and stiff, and 
disposed in a scale-like fashion ; in others, of an 
open, disunited texture, or with the tips divided and 
curiously notched ; and, in the hackled and nicoba? 
pigeons, they are long, acuminate, and laciniated, 
like those of the domestic cock ; and we may a<!d, 
that, in nearly all, they are so constituted as to re- 
flect prismatic colours, when held at various angles 
to the light. 
In their mode of nidification, the majority of the 
Columbidae bears a clo.se analogy to the Insessores ; 
for, with the exception of some few of the ground pi- 
geons, they build their nest in trees. The number 
of eggs laid at each period of hatching is (with the 
above exception) restricted to two, the colour white, 
or ye.llowish-white ; they are incubated by both sexes, 
the male relieving his mate whenever she is com- 
pelled to quit the nest in search of food. The young 
are hatched with merely a thin sprinkling of hairy- 
like down, and are fe<l by their parents in the nest 
till able to fly. At first the food is administered in 
a soft or pulpy state, being thrown up by the old 
birds from their crop, after undergoing a partial di- 
gestion, by w'hich it is rendered a fit nutriment for 
the callow young ; but as they advance in age, it is 
given in a less comminuted form. 
The flight of many of the arboreal, and most of 
