154j on the organs of generation, &C. 
rectum, and the incision extended to the urinary bladder, 
there will now appear a circular orifice, situated at about 
l^\th inches from the opening into the bladder, and pre- 
cisely lx*o^^ inches from the orifices of the seminal ducts 
or vasa defer entia^ which have been already described 
as entering the urethra close to the orifice of the bladder. 
The urethra itself is composed, as M. Cuvier well re- 
marks, of a muscular portion only, included chiefly 
within the pelvis, and wants that which we call vascular. 
Its length from the openings of the vasa deferentia to 
the cloaca is about ly'^^th inches; it is united to the 
lower surface of the rectum, and inclosed with the last by 
a common constrictor muscle. A layer of muscular fibres, 
very strong throughout its whole extent, strengthens its pa^ 
rietes. The penis is withdrawn during its relaxed state 
into a particular pouch, and passes out at the time of erec- 
tion by an orifice formed in the lower paries of the cloaca, 
under that which is peculiar to the urine. It is short, 
nearly cylindrical, and terminated on each side by two small 
rounded lobes corresponding with the glans penis, each in 
a great measure covered by its respective prepuce. When 
this prepuce is opened, four small conical papillae, or nip- 
ples, appear on the surface of either glans. The surface of 
the penis is extremely rugose, and more particularly the 
anterior half ; these rugosities terminate in very small coni- 
cal papillae, which might at first sight be mistaken for small 
bristles. If the sheath containing the penis be now slit up^ 
the anatomy of the whole parts becomes distinct ; the ori- 
fice on the lower surface of the urethra is proved to be the 
opening by which the seminal fluid passes from the com- 
mon urethra into the canal of the penis, destined for the 
transmission of the seminal fiuid, and that secreted by the 
glands of Cowper only. To make this evident, \vc must 
