and from the head of each of the two testicles the two
ducts extend until they coalesce in front at the penis. The duct
that bends back again and that which is in contact with the testicle
are enveloped in one and the same membrane, so that, until you draw
aside the membrane, they present all the appearance of being a
single undifferentiated duct. Further, the duct in contact with the
testicle has its moist content qualified by blood, but to a
comparatively less extent than in the case of the ducts higher up
which are connected with the aorta; in the ducts that bend back
towards the tube of the penis, the liquid is white-coloured. There
also runs a duct from the bladder, opening into the upper part of
the canal, around which lies, sheathwise, what is called the 'penis'.