284 The Naturalist 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, without an instinct so common r 

 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 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, 

 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 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 



