542 LIFE : OUTLINES OF GENERAL BIOLOGY 



the needs of physiological explanations also; and thus and from its 

 basal conception of metabolism onwards. Still, we have also frankly 

 to confess much the same inability precisely to apply this to the 

 forms and behaviour of the nuclear elements — the chromosomes for 

 special instance — as their observers as yet do in the converse way. 

 Here, in fact, further research is needed from both sides; and this 

 seems bringing increasing promise of harmony; as seems probable 

 from recent work, sucli as tliat of Crew, one of our ablest investigators 

 of genetics and sex. 



Vet beyond this we have ventured much further, as to the applica- 

 tion of this sex-contrast, with its physiological interpretation — as 

 of more passive, vegetative, and enduring femaleness, with more 

 active and katabolic, so less enduring maleness — into the never- 



Sex -dimorphism as Shown in the Contrasted Beaks of the Male (A) and the 

 Female (B) of the New Zealand Huia (Heteralocha acutirostris) . The 

 cock chisels away the decayed bark, while the long-beaked hen probes 

 the crevices for insects, thus illustrating division of labour as well as 



dimorphism. 



ending problem of the origins of species, and even genera, orders, 

 etc., and even to the fundamental divergence of plants and animals 

 themselves. That allied species, genera, and groups of many kinds 

 — witness sheep and goats, cattle and buffaloes, or bees and wasps, 

 moths and butterflies, etc., are strikingly feminoid and masculoid in 

 general aspect respectively, and that this contrast prevails even in 

 habits, and so in psychology, so far as we can discern it, is a concep- 

 tion we again submit as worth thinking over, and testing more and 

 more extensively throughout many branches of taxonomy. We do 

 not claim that we can always verify this: but it is surely significant 

 to fmd it so frequently recurrent, as a steady scrutiny of the collec- 

 tions of any great museum will show. In this connection, too, it is 

 worth recaUing that in a good few species the sexes have at first 

 been referred to different genera by taxonomists, witness, for 

 instance, among the amphipod Crustaceans, Praniza and Anceus, 

 now united under the former name. This contrast seems related to 



