490 LIFE : OUTLINES OF GENERAL BIOLOGY 



for believing that somatic modifications may be directly transmitted, 

 in some degree at least. This raises the whole question of the trans- 

 mission of somatic modifications, which we waive. We simply 

 express our opinion, argued for elsewhere, that the evidence does 

 not warrant an acceptance of Cunningham's theory. 



Surplusage Theory. — Hesse and Doflein have made the inter- 

 esting suggestion that as reproduction is very much less expensive 

 in the males, they have surplus material at their disposal which 

 • may account for their frequently greater variability, for certain 

 characteristics of habit and temj^erament, and for their exuberant 

 growths of various sorts. 



To the objection that the male is often much smaller than the 

 female, and that his nutritive income will be proportionally less, 

 the answer is given that the decisive fact is one of ratio, e.g. between 

 the amount of material expended in reproduction and the weight of 

 the body in the two sexes, or between the size of the reproductive 

 organs and the size of the body in the two sexes. 



In cases where the sexes expend approximately equal amounts of 

 material in reproduction, almost no sex differences occur. Thus in 

 many fishes, such as the herring, the ovaries and testes are about 

 the same size and enormous quantities of milt are shed by the 

 males in the water. In the viviparous Cyprinodonts, on the other 

 hand, where there is internal fertilisation and economy of sperm- 

 material, the males show both permanent and periodic distinguishing 

 features. 



In his critique of the surplusage theory, Kammerer indicates 

 some serious, and indeed fatal, objections, (a) It may explain how 

 the male has a good deal to spend on decoration, but it sheds no 

 light on the specific line that his expenditure takes — a mane for the 

 lion and antlers for the stag, (b) It is easy to pick out cases that suit 

 the theory, but what of the broad fact that in hundreds of cases 

 among birds and mammals, reptiles and insects, the two sexes are 

 equal in size, equal in numbers, and uniform in appearance, although 

 the expenditure on the male's side is very much less than that of 

 the female? (c) The female reproduction is physiologically more 

 expensive, but yet it is the female that tends to fatten. And why is 

 it that when her reproductive expenditure is over, her accessory 

 sex-characters do not improve (except in rare cases), but become 

 less marked than ever? (d) There are many cases where the male 

 has to fertilise the eggs of many females, and where he has no 

 masculine peculiarities, which is what the theory would suggest. 

 But there are also many cases of a similar sort, where the polyga- 

 mous male, like peacock, pheasant, stag, bull, sea-lion, shows an 

 exuberance of masculine features. Indeed, it has been suggested 

 that increased sexual function in the male tends to increase the 

 masculine features, and vice versa. 



