THE SEXES, AND CRITICISM OF SEXUAL SELECTION. 25 



stated, namely, in the physiological constitution of males and females 

 themselves. In short, the present position allows some truth in both 

 these conclusions, but regards gay coloring as the expression of the 

 predominantly katabolic or male sex, and quiet plainness as equally 

 natural to the predominantly anabolic females. On this view, too, we 

 are able to restate part of the position emphasized by Brooks. The 

 greater variability of the males is indeed natural, if they be the more 

 katabolic sex. In preponderant katabolism, the combinations and 

 permutations of molecules which constitute variation, are necessarily 

 more probable than in the quiescent, passive, or anabolic females. 

 No special theory of heredity is required, — the males transmit the 

 majority of variations, because they have most to transmit. 



At a later stage something more will be said of natural selection, 

 and its limits as an explanation of facts. But it is here desirable to 

 emphasize that just as we admit the importance of sexual selection as a 

 minor accelerant in the differentiation of the sexes, so we are bound to 

 recognize that natural selection is also continually in operation as a 

 check to a divergence of the sexes which would otherwise tend to 

 become extreme. If this retarding influence of natural selection on the 

 evolutionary process were not continually present, we should find 

 cases like Boncllia and the rotifers much commoner than they are 

 among animals. But it is an error to exaggerate this limiting action 

 into an explanation of the process itself. It should also be noted that 

 both the retarding action of natural selection and the accelerant action 

 of sexual selection become of increasing importance as we ascend the 

 series. And thus, indeed, we are impelled toward a heresy which, as 

 we shall see later, has bearings against the theory of natural selection, 

 which overpass the limits of our present theme. 



Postscript. — Dr. T. W. Fulton, Naturalist to the Scottish 

 Fishery Board, has been good enough to furnish us with some of his 

 results on the size and numerical proportions of male and female fishes. 

 (1) The females are usually considerably more numerous than the 

 males, and never less numerous except in the angler and the catfish. 

 The proportions of females to males among flatfishes ranges from about 

 1-1 in the flounder to about 12-1 in the long rough dab. Among 

 "round" fishes the same proportion varies from about 3-2 in the cod 

 to 9-2 in the common gurnard. (2) The female is longer and larger 

 among all the flatfishes, sometimes by as much as 30 per cent. In 

 cod, haddock, angler, and catfish, the males are larger, while in the 

 whiting the females are slightly larger, and in the common gurnard 

 decidedly so. The subject is being worked up by the above-named 

 naturalist, and can not fail to yield very valuable results. 



