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IOWA ACADEMY OF SCIENCES. 



barbatus), in which the male weighs two and one-half times as much as the 

 female, and polygamy prevails, would illustrate this stage in the process. 



5th. Polygamy having become a fixed habit, all the conditions would tend 

 to accelerate the divergence in size between the sexes. The selection by 

 which the bulkiest and most pugnacious males would succeed in obtaining 

 the females would be as rigorous as could well be conceived, and would 

 result in very great sexual disparity. The males would become remarkably 

 fierce and aggressive. The females, on the contrary, would become less 

 and less disposed to offer any resistance to the males, and hence a remark- 

 able difference in temperament would eventually separate the sexes. The 

 males would be intensely pugnacious, jealous, and aggressive, while the 

 females would be gentle, indifferent, and passive. 8 



Polygamy having become established, the causes or conditions which aided 

 in its establishment would tend to its intensification to such an extent that 

 some males would have scores of females in their harems, while others, 

 indeed the majority, would be entirely deprived of marital rights. Such, in 

 brief, is the state of affairs among the sea lions, of which the fur seal [Cal- 

 lorhinus ursinus) is the best example. 



The above hypothetical history of events will serve to convey the writer's 

 opinion as to what may have been the stages by which polygamy has arisen 

 and become intensified among Piunipedia. For the sake of the nonscientific 

 reader, it may be well to say that there is no intention to convey the idea 

 that the fur seal was first a walrus, then a seal, and finally evolved into a 

 sea lion or fur seal. 



Two other points deserve mention in connection with this highly interest- 

 ing animal. 



The question naturally arises, why do not the females increase in size by 

 inheriting the increased bulk of the male? There ai'e few more interesting 

 and perplexing laws than those of inhei'itance, and among these one of the 

 most elusive is the inheritance of certain characteristics by one sex alone. 

 Darwin attempts to explain these facts by the hypothesis of' pangenesis,— a 

 theory which seems to have few, if any, supporters at present. Whatever 

 may be the cause of the transmission of certain characters to one sex only, 

 there are two facts that may help us to understand the disparity between 

 the sexes of the fur seals: 



1st. The great size of the male is purely a secondary sexual character, and 

 as such would not be expected to be inherited by the female, whatever may 

 be the reason or cause ultimately found to explain the fact. 



2d. Small size is of direct advantage to the female in this case, and hence 

 a natural selection'' would tend to intensify this feature, or what is prac- 



8 Curiously enough, Darwin quotes Captain Bryant to the effect that the females of 

 the fur seal "appear desirous of returning to some particular male" (Descent of Man, 

 p. 257). A careful perusal of the detailed accounts of the habits of this animal collated 

 t)y~Alien, in his Monograph of North American Pinnipeds, fails to discover any exer- 

 cise of choice whatever on the part of the female. It may further he said that even if 

 she had a choice there would be no chance toe.xercise it, as she is immediately pounced 

 upon by the nearest male upon landing, and usually handed about by the scruff of 

 the neck by several males before finding her ultimate resting place. 



9The selection here spoken of can hardly be termed a sexual selection, as the advan- 

 tage accrues directly to the mother, and does not have the direct and exclusive bear- 

 ing upon the reproductive act which is the essence of sexual selection. It is, of course, 

 true that one sex alone is affected; but this fact alone is not sufficient to stamp it as 

 sexual selection as set forth by Darwin. 



