Chap. XVI. INHERITANCE, LIMITED BY AGE. 
185 
aria. In almost the whole large group of thrushes 
the young have their breasts spotted — a character 
Avhich is retained by many species throughout life,, 
but is quite lost by others, as by the Turdus migra- 
torius. 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 
genera when adult are similarly marked. In some 
closely-allied and resplendent Indian cuckoos (Chryso- 
coccyx), the species when mature differ considerably 
from each other in colour, but the young cannot be dis- 
tinguished. The young of an Indian goose {Sarhidiornh 
melanonotus) closely resemble in plumage an allied 
genus, Dendrocygna, when mature.^ Similar facts will 
hereafter be given in regard to certain herons. Young 
black grouse {Tetrao tetrix) resemble the young as well 
as the old of certain other species, for instance the red 
grouse or T. scoticus. Finally, as Mr. Blyth, who has 
attended closely to this subject, has well remarked, the 
natural affinities of many species are best exhibited in 
their immature plumage ; and as the true affinities of 
all organic beings depend on their descent from a 
common progenitor, this remark strongly confirms the 
belief that the immature plumage approximately shew& 
us the former or ancestral condition of the species. 
^ In regard to thrushes, shrikes, and woodpeckers, see Mr. Blyth, in 
Charlesworth’s * Mag. of Nat. Hist.’ vol. i. 1837, p. 304 ; also footnote 
to his translation of Cuvier’s ‘ Regne Animal,’ p. 159. I give the case 
of Loxia from Mr. Blyth’s information. On thrushes, see also Audubon,. 
‘ Ornith. Biography,’ vol. ii. p. 195. On Chrysococcyx and Chal- 
cophaps, Blyth, as quoted in Jerdon’s ‘ Birds of India,’ vol. iii. p. 485. 
On Sarkidiornis, Blyth, in ‘ Ibis,’ 1867, p. 175. 
