192 HABITS OF BIRDS. 
the hilarity of the former. This little bird sings 
likewise in the spring.’”’* 
The researches of comparative anatomy have 
thrown much light upon the peculiar structure of 
song-birds, though there remain still many points of 
interest for future investigation. This, indeed, was 
a subject taken up by the earlier naturalists, and 
most of their observations have been subsequently 
confirmed and extended. Among other curious facts, 
it is stated in Clayton’s Letters from Virginia, that 
Dr. Moulin discovered that in birds, contrary to 
what takes place in man and in quadrupeds, there 
is almost a direct passage from one ear to the other ; 
so that, if the drum (tympanum) of both ears be 
pierced, water, when poured in, will pass from the 
one to the other. There is no spiral shell (cochlea), 
but a small passage which opens into a cavity form- 
ed by two plates of bone that constitute a double 
scull all round the head. The outer plate of bone 
is supported by many hundreds of small threadlike 
columns, or, rather, fibres. Now this passage was 
observed to be much larger in singing-birds than in 
others that do not sing; so very remarkably so, that 
any person to whom the difference has once been 
shown, may easily judge by the head what bird has 
the faculty of singing, though he may be otherwise 
ignorant of its habits.| We have not seen any 
notice of this singular circumstance by any other 
inquirer. 
The remarks of Syme upon this subject are ap- 
propriate and, so far as we know, correct. “The 
notes,” he tells us, ‘of soft-billed birds are finely 
toned, mellow, and plaintive ; those of the hard-bill- 
ed species are sprightly, cheerful, and rapid. This 
difference proceeds from the construction of the vo- 
eal organs. As a large pipe of an organ produces 
* Journal of a Naturalist, p. 265, 3d edit. 
t Miscellanea Curiosa, iii., 291. 
