OF THE SPERM WHALE, 
123 
only for the insertion of the crura, and not for the sup- 
port of any other part, like the pelvis of those animals 
which have posterior extremities ; neither do they meet 
at the forepart or join the vertebrae of the back. The 
erectores penis are very strong muscles, having an origin 
and insertion similar to those of the human subject. 
The acceleratore muscles are likewise very strong ; and 
there is a long and strong muscle, arising from the anus, 
and passing forwards to the bulb of the penis, that runs 
along the under surface of the urethra, and is at last 
lost or inserted in the corpus spongiosum. 
This muscle draws the penis into the prepuce, and 
throws that part of the penis that is behind its insertion 
into a serpentine form. It is common to most animals 
that draw back the penis into what is called its sheath, 
and may be called the retractor penis. In all the females 
which I have examined, the parts of generation are very 
uniformly the same, consisting of the external opening, 
the vagina, the two horns of the uterus, fallopian tubes, 
fimbriae, and ovaria. 
The external opening is a longitudinal or oblong 
fissure, whose edges meet in two opposite points, and 
the sides are rounded off so as to form a kind of sulcus. 
The skin and parts on each side of this sulcus are of a 
looser texture than on the common surface of the animal, 
not being loaded with oil, and allowing of such motion 
of one part and another as admits of dilation and con* 
traction. The vagina passes upwards and backwards 
towards the loins, so that its direction is diagonal re- 
specting the cavity of the abdomen, and then divides 
