390 CHORDATA. 
inguinal canals. Through each of these canals there passes 
a spermatic cord with genital artery and vein to the testis from 
the lumbar region. The testis is partially surrounded by 
an epididymis consisting of coiled tubes, the vasa efferentia, 
which unite to form the vas deferens. This duct leaves the 
scrotal sac by the inguinal canal and passes up round the 
ureter of the same side, then backwards to open into the 
urethra. The testes in the young rabbit occupy the normal 
position in the neighbourhood of the kidneys, but by a 
process called the descensus testiculorum they pass down- 
wards and into the scrotal sacs. 
The swollen base of the two vasa deferentia, as they 
enter the urethra, is often termed the wéerus masculinus. In 
the same position are the prostate glands opening into the 
urethra, and posterior to them are a pair of Cowjer’s glands. 
The urethra passes along the posterior surface of the fevzs, 
which is formed of vascular erectile tissue. 
In the female the ovaries are small oval bodies attached 
by mesentery to the dorsal abdominal wall. The ovzducts 
are paired tubes of the same size. Each has three parts, 
viz::—the anterior portion or Fallopian tube, of small calibre, 
and opening into the abdominal cavity by a large funnel ; 
the middle portion or uterus, which has thick muscular 
walls and is used for the retention of the young during 
gestation ; the third portion or vagina, which in the rabbit 
is fused with its fellow, resulting in a single wide vagina, at 
the anterior end of which opens the os of each uterus, and 
posteriorly it leads into the urethra which is, in the female, 
known as the vestibule, There are Cowper's glands, as in 
the male, and a vestigial penis called the chtorvis. The 
opening to the exterior is called the vulva. 
The brain may be isolated by careful removal of the roof 
of the skull. It is chiefly remarkable for very large cerebral 
hemispheres which are connected across by a 
large band called the corpus callosum, for the 
lateral expansion and coiling of the cerebellum, for the 
division of the optic lobes into four, called the corpora 
guadrigemina, and for the presence of fwe/ve cranial nerves, 
the spinal accessory and hypoglossal being added to the ten 
of the skate. 
Nervous. 
