322 MR. J. L. BONHOTE ON THE [June 18, 



The SoDg-Thrush, Missel Thrush, Eedwing, and hen Blackbird have 

 the usual Thrush marking, viz. PI. XX. fig. 8, which I take to be 

 a shortening of the primitive lougitudinal streak ; in the young 

 of the Missel Thrush, and sometimes in the case of the Song- 

 Thrush, the terminal light edgings are visible. In the Fieldfare 

 (Plate XX. fig. 9) we may note the terminal spot much enlarged, 

 with a tendency to become light in the centre and form the V-shaped 

 markings, whilst in White's Thrush the markings are crescentie. 

 A Table of the Thrushes drawn from the original tree would 

 make them break off from the 4th line in the main tree. 



Heart-shaped markings Heart-shaped marking split Heart-shaped marking ovate, 



forming crescent. in centre to form V-shaped no bars above (Fig. 8. 



{Turdus varius.) marking. (Breast of T. PL XX.). Breast of T. ms- 



pilaris. Young of T. vis- civorus, T. musicus, T. ilia- 



civorus.) cus, J T. merula. 



Two longitudinal stripes along the centre of 

 either vane, with light rhachis. 



The longitudinal stripes joined, leaving only 

 a light terminal spot. 



Self-coloured feather. 

 (cJ T. merula and. back of T. pilaris. T. iliacus. T. musicus. T. viscivorus.) 



Judging from pattern alone, we should therefore be led to 

 classify them in the following order, starting from the highest 

 form : — 



(1) T. merula. (2) T. musicus. (3) T. viscivorus. (4) T. pilaris. 

 (5) T. iliacus. (6) T. varius. 



T. iliacus is placed after T. pilaris owing to the markings on 

 the breast being of a slightly more primitive type. This sug- 

 gestion, however, is only given as showing how a study of the 

 pattern might be applied. 



It would make the paper too long and tedious to take many 

 examples of the Passeres, and necessitate a careful examination of 

 a large series of young birds, which, unfortunately, I have not at 

 hand. It may be mentioned, however, as I have noted them, that 

 the back of the young Spotted Flycatcher greatly resembles that of 

 the young Missel Thrush, and that the markings of a young Haw- 

 finch are very similar to those of White's Thrush. Plate XX. fig. 1 

 represents a feather from the breast of the Wren, showing how the 

 A-marking, most clearly visible in the Nutcracker, might be 

 brought about if it did not follow the line shown in the Thrushes. 



In the Wryneck we find the young with a barred plumage on 

 the breast, while the adult has the V-sbaped markings ; and on 

 reference to the table it will be noticed that it has followed the form 

 'of evolution shown in the centre or main line, the only difference 



