cristata), the head is covered by a great hood or bladder. This is
supported by the septum of the nose, which is produced far backwards
and rises into an internal crest seven inches in height. The hood is
clothed with short hair, and is muscular; can be inflated until it more
than equals the whole head in size! The males when rutting, fight
furiously on the ice, and their roaring is said to be sometimes so
loud as to be heard four miles off. When attacked they likewise roar
or bellow; and whenever irritated the bladder is inflated and quivers.
Some naturalists believe that the voice is thus strengthened, but
various other uses have been assigned to this extraordinary structure.
Mr. R. Brown thinks that it serves as a protection against accidents of
all kinds; but this is not probable, for, as I am assured by Mr. Lamont
who killed 600 of these animals, the hood is rudimentary in the
females, and it is not developed in the males during youth. (8. On the
sea-elephant, see an article by Lesson, in Dict. Class. Hist. Nat.
tom. xiii. p. 418. For the Cystophora, or Stemmatopus, see Dr. Dekay,
Annals of Lyceum of Nat. Hist. New York, vol. i. 1824, p. 94. Pennant
has also collected information from the sealers on this animal. The
fullest account is given by Mr. Brown, in Proc. Zoolog. Soc. 1868, p.
435.)
ODOUR.
With some animals, as with the notorious skunk of America, the
overwhelming odour which they emit appears to serve exclusively as a
defence. With shrew-mice (Sorex) both sexes possess abdominal
scent-glands, and there can be little doubt, from the rejection of
their bodies by birds and beasts of prey, that the odour is protective;
nevertheless, the glands become enlarged in the males during the
breeding-season. In many other quadrupeds the glands are of the same
size in both sexes (9. As with the castoreum of the beaver, see Mr.
L.H. Morgan s most interesting work, The American Beaver, 1868, p.
300. Pallas ( Spic. Zoolog. fasc. viii. 1779, p. 23) has well
discussed the odoriferous glands of mammals. Owen ( Anat. of
Vertebrates, vol. iii. p. 634) also gives an account of these glands,
including those of the elephant, and (p. 763) those of shrew-mice. On
bats, Mr. Dobson in Proceedings of the Zoological Society 1873, p.
241.), but their uses are not known. In other species the glands are
confined to the males, or are more developed than in the females; and
they almost always become more active during the rutting-season. At
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