1 84 SEXUAL SELECTION : BIRDS. Part U. - 



are marked with feeble stripes or rows of spots, and as 

 many allied species both young and old are similarly 

 marked, no naturalist, who believes in the gradual 

 evolution of species, will doubt that the progenitor of 

 the lion and puma was a striped animal, the young 

 having retained vestiges of the stripes, like the kittens 

 of black cats, which when grown np are not in the least 

 striped. Many species of deer, which when mature are 

 not spotted, are whilst young covered with white spots, 

 as are likewise some few species in their adult state. 

 So again the young in the whole family of pigs (Suidae), 

 and in certain rather distantly-allied animals, such as 

 the tapir, are marked with dark longitudinal stripes ; 

 but here we have a character apparently derived from 

 an extinct progenitor, and now preserved by the young 

 alone. In all such cases the old have had their colours 

 changed in the course of time, whilst 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 distantly-allied birds such as ostriches, are 

 whilst covered wdth down longitudinally striped ; but 

 this character points back to a state of things so re- 

 mote 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 I'emale siskin, as well 

 as the young of the goldfinch, greenfinch, and some 

 other allied species. The young of many kinds of 

 buntings (Emberiza) resemble each other, and like- 

 wise the adult state of the common bunting, E. mili- 



