The Descent of Man

inheritance, that is, on parts acquired by one
sex having been partially transmitted to the
other. I will in this place only give some instances
of such rudiments. It is well known that
in the males of all mammals, including man,
rudimentary mammae exist. These in several
instances have become well developed, and
have yielded a copious supply of milk. Their
essential identity in the two sexes is likewise
shewn by their occasional sympathetic
enlargement in both during an attack of the
measles. The vesicula prostatica, which has
been observed in many male mammals, is now
universally acknowledged to be the homologue
of the female uterus, together with the connected
passage. It is impossible to read
Leuckart's able description of this organ, and
his reasoning, without admitting the justness of
his conclusion. This is especially clear in the
case of those mammals in which the true female
uterus bifurcates, for in the males of these
the vesicula likewise bifurcates. (54. Leuckart,