Now that we have stated the magnitudes, the properties, and the
relative differences of the other internal organs, it remains for us
to treat of the organs that contribute to generation. These organs
in the female are in all cases internal; in the male they present
numerous diversities.

In the blooded animals some males are altogether devoid of
testicles, and some have the organ but situated internally; and of
those males that have the organ internally situated, some have it
close to the loin in the neighbourhood of the kidney and others
close to the belly. Other males have the organ situated externally. In
the case of these last, the penis is in some cases attached to the
belly, whilst in others it is loosely suspended, as is the case also
with the testicles; and, in the cases where the penis is attached to
the belly, the attachment varies accordingly as the animal is
emprosthuretic or opisthuretic.