BIRDS. 529 



which when mature are not spotted, are while young cov- 

 ered with white spots, as are likewise some few species in the 

 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 colors 

 changed in the course of time, while the young have 

 remained but little altered, and this has been effected 

 through tlie 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 Gallinaceaj and of some distantly 

 allied birds, such as ostriches, are covered with longitu- 

 dinally 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 states of the 

 common bunting, E. 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 

 migrator ins. So again with many thrushes, the feathers 

 on the back are mottled before they are moulted for the 

 first time, and this character is retained for life by certain 

 eastern species. The young of many species of shrikes 

 (Lanius), of some woodpeckers and of an Indian pigeon 

 (Chalcophaps indicus) are transversely striped on the 

 under surface; and certain allied species or whole genera 

 are similarly marked when adult. In some closely allied 

 and resplendent Indian cuckoos (Chrysococcyx) the mature 

 species differ considerably from one another in color, but 

 the young cannot be distinguished. The young of an 

 Indian goose {^Sarkidiornis melanonotus) closely resemble 

 in plumage an allied genus, Dendrocygna, when mature.* 



* In regard to thrushes, shrikes and woodpeckers, see Mr. Blyth, 

 Charlesworth's ''Mag. of Nat. Hist.," vol. i, 1837, p. 304; also 



