196 WALTKR KIDD, ESQ., M.D., F.Z.S., 



selection is but a part of natural selection, viewed broadly 

 and apart from heredity. Sexual selection is tauglit for 

 the purpose of supplyini^ the obvious inadequacy of natural 

 selection, and is admittedly appli(;able, when it seeks to 

 account for beauty of form, colour and markin<):s. only to 

 those hiG:lier animalp which have snfHcient intellig-ence to 

 come under its sphere. Here is a vast wealth of beauty of 

 lower invertebrate life wholly outside sexual selection ! The 

 beauty of this class has to find another explanation, and it finds 

 it in accident the bye-products of chemical processes supplyini;- 

 a parallel. The fact that beauty among these life- forms is not 

 universal is taken in proof of this theory of accident ; but 

 beauty is no more universal in monkeys (even if not nearly 

 absent), many classes of ungulate mammals, cetacea, reptiles, 

 among allied clafises of which sexual selection is supposed to 

 operate in the production of facts of beauty. One more great 

 class of forms of life which come neither under natural selec- 

 tion nor sexual selection, and Avliich Romanes declares to 

 constitute half of the animal species of the world, is that 

 of parasites, largely degenerate animals. The beauty of 

 colouring and form of plants, the gaily-coloured coroll^e, 

 variegated leaves, numerous markings, and attractive fruits 

 are accounted for by the theory of natural selection, owing 

 to the fact that so large a proportion of these are fertilized by 

 birds and insects, and that these attractions bring aliout a 

 form of selection and survival of the fittest among plants, 

 their gay fruit and flowers leading to the swallowing of the 

 seeds by birds, and conveyance of pollen by insects to other 

 plants, with obvious results. For that class of })lants, 

 which, whether hermaphrodite or not, are fertilized in 

 this mediate manner, this explanation is good enough. But 

 there remains a class of plants directly self-fertilized, or 

 fertilized by the action of wind, which also are necessarily 

 removed from the range of sexual selection and yet not 

 destitute of beauty. This class is very much smaller than 

 that in which cross-fertilization takes place, as Darwin 

 shows. In illustration of it he mentions two lists each of 

 forty-m'ne genera Avliich he examined. In the first* list 

 fertilization l)y insects Avas proved, and of these forty-nine 

 there were about thirty-two Avhich had asymmetrical flowers 

 or presented remarkable peculiarities. The second list of 

 forty-nine genera, including species which wero fully or 



* Cross and Self- Fertilization of riants, p. 371. 



