284 The Nahtralist in La Plata. 
moment. Meanwhile, the dull-plumaged female is 
not seen and not heard: for not even a skulking 
crake lives in closer seclusion under the herbage — 
so widely have the sexes diverged in this species. 
Is the female, then, witkout an instinct so common r 
— kas ske no sudden fits of irrepressible gladness ? 
Doubtless ske kas tkem, and manifests tkem down 
in ker place of concealment in lively ckirpings and 
quick motions — tke simple, primitive form in wkick 
gladness is expressed in tke class of birds. In tke 
various species of tke genus Cnipolegus, already 
mentioned, the difierence in tke sexes is just as 
great as in tke case of tke troupial : tke solitary, 
intensely black, statuesque mmle kas, we have seen, 
a set and highly fantastic performance; but on 
more than one occasion I have seen four or five 
females of one species meet together and have a 
little simple performance all to themselves — ^in form 
a kind of lively mock fight. 
It might be objected that when a bird takes its 
stand and repeats a set finished song at intervals 
for an hour at a stretch, remaining quietly perched, 
suck a performance appears to be different in 
character from tke irregular and simple displays 
wkick are unmistakably caused by a sudden glad 
impulse. But we are familiar with tke truth that 
in organic nature great things result from small 
beginnings — a common flower, and our own bony 
skulls, to say nothing of the matter contained within 
tkem, are proofs of it. Only a limited number of 
species sing in a highly finished manner. Looking 
at many species, we find every gradation, every 
shade, from the simple joyous chirp and cry to the' 
