The Descent of Man

and in the case of the Marsupials, that both
sexes carried their young in marsupial sacks.
This will not appear altogether improbable, if
we reflect that the males of existing syngnathous
fishes receive the eggs of the females in
their abdominal pouches, hatch them, and afterwards,
as some believe, nourish the young
(30. Mr. Lockwood believes (as quoted in
'Quart. Journal of Science,' April 1868, p. 269),
from what he has observed of the development
of Hippocampus, that the walls of the abdominal
pouch of the male in some way afford nourishment.
On male fishes hatching the ova in
their mouths, see a very interesting paper by
Prof. Wyman, in 'Proc. Boston Soc. of Nat. Hist.'
Sept. 15, 1857; also Prof. Turner, in 'Journal of
Anatomy and Physiology,' Nov. 1, 1866, p. 78.
Dr. Gunther has likewise described similar cases.);—
that certain other male fishes hatch the
eggs within their mouths or branchial cavities;—that
certain male toads take the chaplets
of eggs from the females, and wind them round