344 H - H - NEWMAN. 



there is in the female a transition from a primitive cross-banded 

 pattern to one characterized by longitudinal stripes. This is the 

 opposite order of change from that given by Eimer and shows 

 that his laws of orthogenetic variation have only a limited appli- 

 cation. We have here a clear case of orthogenetic variation 

 during ontogeny, a phenomenon that Gadow tried unsuccessfully 

 to show in the case of scutes of Chelonia. 



The total male plumage cannot be considered as primitive, 

 the spawning plumage proper being secondary, an especial male 

 acquisition due to his superabundant vitality. The cross-banded 

 pattern is probably primitive and was possessed by both sexes. 

 Even the distinct spot on the dorsal fin in the males of various 

 species of Fundiilus was probably a character common to both 

 sexes, for in the allied species Cyprinodon we find this marking 

 more pronounced in the female, but often present in rather vague 

 form in the males. 



Whether differences in the relative abundance of the sexes can 

 be explained as adaptations is open to discussion. The fact that, 

 in all the species studied, the males are relatively rare may be 

 explained by the law of economy, for comparatively few males 

 are quite capable of fecundating the eggs of many females, hence 

 any more males would be superfluous. The experiment of put- 

 ting too large a proportion of males in aquaria with females 

 shows the disadvantage of a superfluity of males, for they spend 

 most of their time fighting instead of devoting their attention to 

 spawning. 



The more slender body form of the males in Fundulus and the 

 deeper but more compressed bodies of the males of Cyprinodon 

 are probably both adaptions to the more active and combative 

 disposition of that sex. 



Of the temporary characters that accompany the sexual climax 

 in both sexes, the heightened color of the males is most readily 

 explained on purely physiological grounds. It is well known 

 that heightened vigor, whether reproductive or somatic, is ac- 

 companied by a more active metabolism, and it is equally well 

 known that pigmentation is a sort of index of the rate of metabolism 

 in an organism. A heightened sexual vigor is then necessarily 

 accompanied by an increase in pigmentation. So much for that 



