SEXUAL SELECTION 599 



liever in evolution will doubt that the progenitor of the 

 lion and puma was a striped animal, and that the young 

 have retained vestiges of the stripes, like the kittens erf 

 black cats, which are not in the least striped when grown 

 up. Many species of deer which when mature are not 

 spotted are while young covered with white spots, as are 

 likewise some few species in the adult state. So again the 

 young in the whole family of pigs (Suidse), and in certain 

 rather distantly allied animals, such as the tapir, are marked 

 with dark, longitudinal stripes; but here we have a char- 

 acter apparently derived from an extinct progenitor, and 

 now preserved by the young alone. In all such cases the 

 old have had their colors changed in the course of time, 

 while the young have remained but little altered, and this 

 has been effected through the principle of inheritance at 

 corresponding ages. 



This same principle applies to many birds belonging to 

 various groups, in which the young closely resemble each 

 other, and differ much from their respective adult parents. 

 The young of almost all the Gallinacese, and of some dis- 

 tantly allied birds, such as ostriches, are covered with lon- 

 gitudinally striped down; but this character points back to 

 a state of things so remote that it hardly concerns us. Young 

 cross-bills (Loxia) have at first straight beaks like those of 

 other finches, and in their immature striated plumage they 

 resemble the mature redpole and female siskin, as well as 

 the young of the goldfinch, greenfinch and some other allied 

 species. The young of many kinds of buntings (Emberiza) 

 resemble one another, and likewise the adult state of the 

 common bunting, £!. miliaria. In almost the whole large 

 group of thrushes the young have their breasts spotted — a 

 character which is retained throughout life by many species, 

 but is quite lost by others, as by the Turdus migratorius. So 

 again with many thrushes, the feathers on the back are mot- 

 tled before they are moulted for the first time, and this char- 

 acter is retained for life by certain eastern species. The young 

 of many species of shrikes (Lanius), of some woodpeckers, 



