284 The Naturalist in La Plata. 
moment. Meanwhile, the dull-plumaged female is 
not seen and not heard: for not evena skulking 
crake lives in closer seclusion under the herbage— 
so widely have the sexes diverged in this species. 
Is the female, then, without an instinct so common ? 
—has she no sudden fits of irrepressible gladness ? 
Doubtless she has them, and manifests them down 
in her place of concealment in lively chirpings and 
quick motions—the simple, primitive form in which 
gladness is expressed in the class of birds. In the 
various species of the genus Cnipolegus, already 
mentioned, the difference in the sexes is just as 
great as in the case of the troupial: the solitary, 
intensely black, statuesque male has, 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 themselyes—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, 
such a performance appears to be different in 
character from the irregular and simple displays 
which are unmistakably caused by a sudden glad 
impulse. But we are familiar with the 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 
them, are proofs of it. Only a lhmited number of 
species sing ina highly finished manner. Looking 
at many species, we find every gradation, every 
shade, from the simple joyous chirp and cry to the 
