Lij'e-liisiory cf iSal/non. 119 



The facts sliown by the authors speak for tlieinselves. I 

 submit that I hey afford considerable support to my views if 

 we regard the common Sahnou as an instance of a species in 

 vhich the pathological results of spawning and their fatal 

 issue have undergone much modification. Whether, how- 

 ever, my views be accepted or not, it is of great importance 

 and interest to have so clearly put before us the details of the 

 exchange of material from one part of the body to the other 

 under the influence of the generative ovirans. 



The fact that the destination of much of the material thus 

 lost from the muscles (70 per cent, in the case of fats, 77 per 

 cent, in that of proteids, and a large proportion in that of phos- 

 phorus) is unknown is very significant. Some of it is, no 

 doubt, used, as the authors suggest, as a source of energy; but 

 1 look to this surplus material for the formation of secondary 

 sexual characters, as indeed is suggested in the case of the 

 salmon's beak and in the deposition — apparently almost adven- 

 titiously — of some of the moving muscle-pigments in the 

 fisii's skin. There can, I think, be little doubt that given an 

 animal wherein a considerable amount of surplus material and 

 pigment is on the move, much of that material and pigment 

 would, with an increased blood-supj)ly, be at the service of 

 and directed to, not only the genitalia, but to such other 

 portions of the body as undergo special exertion or movement 

 during courtshii), an idea which I borrow gratefully from 

 Dr. Cunningham. 



It seems logical to presuppose that such a transference will 

 be found to accompany the seasons of special sexual activity 

 in other animals, and that upon the relative amount of sur])lu3 

 -energy and nuiterial will depend the decoration or armature 

 of the sexes. In animals whose sexual activity is permanent 

 and not periodic it is probable that such a transference will 

 be less marked, inasmuch as the permanent activity of the 

 generative organs will prevent undue accumulation of fat and 

 other surplus matter in the muscles, and will constantly, 

 under the influence of heredity and natural selection, apply 

 such surplus n.ateiial to the parts where it is most urgently 

 required. 



Further, in the observation that the proportional use of 

 proteids and fats " as a source of energy " is different in male 

 and female salmon we have a most suggestive hint as to the 

 origin of sexual dimoiphism, whether seasonal or otherwise. 

 We have in the Salmon a state of things which, if modified 

 or accentuated by natural selection, might easily be the 

 foundation of tlie numerous extraordinary instances of sexual 

 dimorphism which the animal kingdom presents to us. My 



