And the

connexion between the latter and the glans is called the frenum. The
remaining part of the penis is composed of gristle; it is easily
susceptible of enlargement; and it protrudes and recedes in the
reverse directions to what is observable in the identical organ in
cats. Underneath the penis are two 'testicles', and the integument
of these is a skin that is termed the 'scrotum'.

Testicles are not identical with flesh, and are not altogether
diverse from it. But by and by we shall treat in an exhaustive way
regarding all such parts.