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SEXUAL selection: bikds. 
Part II. 
sliare in hatching the eggs; but the female likewise 
attends to the young.^^ I have not been able to dis- 
cover whether with these species the young resemble the 
adult males more closely than the adult females; for 
the comparison is somewhat difficult to make on account 
of the double moult. 
Turning now to the Ostrich order : the male of the com- 
mon cassowary (Casuarius galeatus) would be thought 
by any one to be the female, from his smaller size and 
from the appendages and naked skin about his head 
being much less brightly coloured ; and I am informed 
by Mr. Bartlett that in the Zoological Gardens it is 
certainly the male alone who sits on the eggs and takes 
care of the young.^^ The female is said by Mr. T. W. 
Wood to exhibit during the breeding-season a most 
pugnacious disposition ; and her wattles then become 
enlarged and more brilliantly coloured. So again the 
female of one of the emus (Dromoeus irroratus) is con- 
siderably larger than the male, and she possesses a 
slight top-knot, but is otherwise undistinguishable in 
plumage. She appears, however, to have greater 
power, when angry or otherwise excited, of erecting, 
^^like a turkey-cock, the feathers of her neck and 
20 For these several statements, see Mr. Gould’s ‘Birds of Great 
Britain.’ Prof. Newton informs me that he has long been convinced, 
from his own observations and from those of others, that the males of 
the above-named species take either the whole or a large share of the 
duties of incubation, and that they “ shew much greater devotion 
“ towards their young, when in danger, than do the females.” So it is, 
as he informs me, with Limosa lapponica and some few other Waders, 
in which the females are larger and have more strongly contrasted 
colours than the males. 
21 The natives of Ceram (Wallace, ‘Malay Archipelago,’ vol. ii. p. 
150) assert that the male and female sit alternately on the eggs ; but 
this assertion, as Mr. Bartlett thinks, may be accounted for by the 
female visiting the nest to lay her eggs. 
22 ‘The Student,’ April, 1870, p. 124. 
