508 Affinities of the feathered Race, 



almost every particular : still it retains a good deal of the 

 true Merula; and it builds a plastered nest, like our thrushes. 

 In M. solitaria the size decreases, the number of breast spots 

 are diminished, the tarse is much lengthened (a character 

 which commences in M. wzustelina), the nest is constructed 

 without plaster, and even the tail is rufous, as in the nightin- 

 gales. M. WilsonzV has the very form of Philomela, and is 

 the smallest bird that ranks in Merula : its breast-spots are 

 but very few, and these appearing as though more than half 

 obliterated; its habits are exactly those of Philomela, and so 

 is its nidification ; and its bill hardly differs from that of our 

 nightingale. The great nightingale of Eastern Europe has, 

 according to Bechstein, an obscurely spotted breast, also a 

 stronger bill than the common species; it is described to be 

 more omnivorous in its diet, and, consequently, to be more 

 hardy in a state of confinement : even its size implies an ap- 

 proach to the small Merulae. And, lastly, look to the nest- 

 ling plumage of the song nightingale (P. jLuscinia), a character 

 of no small importance in indicating the true affinities of birds, 

 and we at once perceive its true station in the system, and 

 how distinct it is from those forms with which (apparently 

 from its mere size) it has been hitherto associated : it is, 

 in fact, an ultimate modification of the type represented by 

 .Merula. 



Let us now compare, for a moment, the extremes of the 

 genus Merula; let us bring together the large mottled-backed 

 thrushes of the East, and those diminutive solitary thrushes 

 of the West. Does it seem proper that these should rank 

 in the same minimum division ? And yet how are they to be 

 separated ? How can the former be divided from those of 

 the missel thrush form * ; the last-mentioned from the field- 

 fare group ; the fieldfares from the merles, or from the con- 

 geries to which the song thrush belongs, which last we have 

 seen to inosculate with the nightingales ? How, in like man- 

 ner, can we divide the genera ^f rdea or Corvus ? 



It indeed appears that, in these very typical genera, there 



* On examining a series of specimens of M. viscivora, it will be seen 

 that many exhibit conspicuous traces of the mottling on the upper parts, 

 particularly on the rump, and that space covered by the tertiary wing 

 feathers ; also on the upper tail-coverts ; the latter being broadly edged 

 with a paler tint, which in the former occupies the centre of each feather. 

 Here we have an interesting illustration, in the plumage of birds, of the 

 gradual developement of a particular marking as we recede from the type. 

 There is also a regular increase in the size of the bill, which, in the missel 

 thrush, is rather small. I am unaware that the form of M. varia and its 

 immediate congeners is further modified, but suspect them rather to be 

 the extreme ramifications in that direction. 



