properly belong to the opposite sex; and it has now been ascertained
that at a very early embryonic period both sexes possess true male and
female glands. Hence some remote progenitor of the whole vertebrate
kingdom appears to have been hermaphrodite or androgynous. (26. This is
the conclusion of Prof. Gegenbaur, one of the highest authorities in
comparative anatomy: see Grundzuge der vergleich. Anat. 1870, s. 876.
The result has been arrived at chiefly from the study of the Amphibia;
but it appears from the researches of Waldeyer (as quoted in Journal
of Anat. and Phys. 1869, p. 161), that the sexual organs of even the
higher vertebrata are, in their early condition, hermaphrodite.
Similar views have long been held by some authors, though until
recently without a firm basis.) But here we encounter a singular
difficulty. In the mammalian class the males possess rudiments of a
uterus with the adjacent passage, in their vesiculae prostaticae; they
bear also rudiments of mammae, and some male Marsupials have traces of
a marsupial sack. (27. The male Thylacinus offers the best instance.
Owen, Anatomy of Vertebrates, vol. iii. p. 771.) Other analogous
facts could be added. Are we, then, to suppose that some extremely
ancient mammal continued androgynous, after it had acquired the chief
distinctions of its class, and therefore after it had diverged from the
lower classes of the vertebrate kingdom? This seems very improbable,
for we have to look to fishes, the lowest of all the classes, to find
any still existent androgynous forms. (28. Hermaphroditism has been
observed in several species of Serranus, as well as in some other
fishes, where it is either normal and symmetrical, or abnormal and
unilateral. Dr. Zouteveen has given me references on this subject, more
especially to a paper by Prof. Halbertsma, in the Transact. of the
Dutch Acad. of Sciences, vol. xvi. Dr. Gunther doubts the fact, but it
has now been recorded by too many good observers to be any longer
disputed. Dr. M. Lessona writes to me, that he has verified the
observations made by Cavolini on Serranus. Prof. Ercolani has recently
shewn ( Accad. delle Scienze, Bologna, Dec. 28, 1871) that eels are
androgynous.) That various accessory parts, proper to each sex, are
found in a rudimentary condition in the opposite sex, may be explained
by such organs having been gradually acquired by the one sex, and then
transmitted in a more or less imperfect state to the other. When we
treat of sexual selection, we shall meet with innumerable instances of
this form of transmission, as in the case of the spurs, plumes, and
brilliant colours, acquired for battle or ornament by male birds, and
inherited by the females in an imperfect or rudimentary condition.
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