s 
46 ANATOMY OF THE RABBIT. 
(8) The urinogenital system, comprising the reproductive 
and excretory organs, together with their common ducts—the 
urethra of the male and the vestibulum of the female—and the 
associated bulbourethral gland. The reproductive organs com- 
prise, in the male, the central organs or testes, and the deferent 
ducts, both of which are paired, the unpaired seminal vesicle, 
and the paired prostatic and paraprostatic glands. In the 
female, the reproductive organs comprise the paired ovaries, 
uterine tubes and uteri, together with the unpaired vagina. 
The excretory organs of both sexes comprise the paired kidneys 
and ureters and the unpaired 
urinary bladder. 
Certain organs of the body 
are not included in this classifi- 
cation: (1) The thymus and 
thyreoid glands are connected 
with the digestive tube in the 
embryonic condition, and_ for 
this reason are sometimes in- 
cluded with the digestive system, 
although in the adult they occur 
as independent structures. (2) 
The suprarenal body is situa- 
ted close to the kidney of either 
ee te Oa SE Be pen gee side, but is independent of the 
mm.):m., mandibular; h., hyoid; 1 and 2, first latter, both in the adult condi- 
and second branchial arches; a.l., antérior 
limb-bud; me., metameres; p.l., posterior +jon and in point of develop- 
limb-bud. (After Minot and Taylor, in 
Keibels Normentafeln, V.; Fig. 12.) ment. (3) The special (olfac- 
tory, optic and auditory) sense- 
organs of the head are highly elaborated structures, the relations 
of which are partly with the central nervous system. 

GENERAL ORGANIZATION. 
In the rabbit, as in all vertebrates, the general plan of organiza- 
tion involves three chief features, as follows: 
(1) Axial orientation. The axial line of the body is indicated 
by the chief portion of the skeleton, and the important organ- 
