Tongue-marks in Young Birds. 577 
found in the young of Lusciniola. Besides those above- 
mentioned, however, I do not think it probable that it occurs 
in any other family inhabiting the Palearctic Region, for 
durmg my research I have been able to amass much 
evidence of a negative kind, all of which points to this 
conclusion. 
Although the colour of the tongue and the inside of the 
mouth ranges from purplish red in some of the Finches to 
bright yellow in the Willow-Warblers, I attach very little 
importance to this, as it is well-known that the colours 
of all the soft parts in birds are subject to many changes 
and variations. 
In shape the tongue is very intimately related to the bill, 
hence it is small and broad in the newly-hatched bird, only 
getting its narrow form with the growth of the bill. A 
similar change takes place in the tongue-marks: these are 
at first short and thick, but they develop simultaneously 
with the tongue, and by the eighth or tenth day attain 
their characteristic shape. ‘This is illustrated in text-fig. 33, 
fig. 15 @, which shews the tongue of a Hedge-Sparrow 
(Accentor modularis) about eleven days old, while fig. 15 6 
was taken from a bird of the same species not more than six 
days old. It is also shown in figs. 1, 2, and 4; for these 
represent tongues of closely-related Acrocephalt taken at 
different ages. In these (as the genus Hypolais, fig. 3) 
the tongue-marks are what I may term of the simple type, 
being a pair of spots situated on the basal half of the 
tongue. In Cisticola (fig. 5) the black marks are greatly 
exaggerated, and Locustella (fig. 6) has a third on the end of 
thetongue. Alauda likewise has three marks ; but in this case 
the bill is also ornamented, there being a spot on the inner 
side of the tips of both mandibles. With the true Warblers 
the marks are not always reliable, being often clouded and 
indistinct, varying considerably in different individuals. In 
figs. 7-Ll (S. cinerea, 8S. atricapilla, 8. hortensis, and 
S. melanocephala) I have given well-marked examples ; in 
some individuals the dark marks may be scarcely perceptible. 
These remarks apply equally to Motacilla rai and M. lugubris 
