In viviparous animals furnished with feet there is outwardly one
and the same duct for the sperm and the liquid residuum; but there are
separate ducts internally, as has been observed in the differentiation
of the organs. And with such animals as are not viviparous the same
passage serves for the discharge also of the solid residuum; although,
internally, there are two passages, separate but near to one
another. And these remarks apply to both male and female; for these
animals are unprovided with a bladder except in the case of the
tortoise; and the she-tortoise, though furnished with a bladder, has
only one passage; and tortoises, by the way, belong to the ovipara.