REGIONAL SECTIONS. IOI 
is continuous with the parietal peritoneum of the abdomen, and thus 
represents a permanent vaginal process. Like other structures 
of the abdominal cavity, the testis itself is covered by peritoneum, 
the latter being designated as the visceral layer of the tunica 
vaginalis propria. This investment is connected with the parietal 
layer by the mesorchium, and in the rabbit it will be observed 
that the latter is chiefly attached forwards on the dorsal wall of the 
abdomen, 7.e., in a position indicating the original situation of the 
testis itself. 
In the female the ovary is closely associated with the dorsal wall 
of the abdomen, and its supporting peritoneum, the mesovarium, 
is insignificant. Its duct in passing backward, however, becomes 
greatly displaced from a dorsal position, and thus comes to be 
supported by a broad fold of peritoneum. The latter is considered 
to consist of two portions, one, the mesosalpinx, being the support 
of the uterine tube, the other, the mesometrium, that of the 
uterus. The entire fold, however, forms a continuous structure, 
and is known in this relation as the broad ligament. 
REGIONAL SECTIONS. 
-The following plate-figures (I-VIII) are from characteristic 
sections of a rabbit-foetus of 56mm., and may be used either in 
connection with the general features of topography as outlined above, 
or for the identification of various minor structures appearing in 
the dissection. 
Certain points regarding the sections are perhaps worthy of 
notice. First, in the longitudinal section illustrated in Plates I and 
II it will be noticed that paired structures frequently appear; this 
being because of the fact that the section is not exactly median, at 
least in certain places. Second, in using sections of the foetus for 
gross anatomical features it is necessary to make allowance in some 
cases for the different proportions of organs, and consequent slight 
differences in position, in the foetal as compared with the adult 
condition. Finally, many of the features appearing in the original 
sections are such as could not be reproduced in the plates, although 
they are indicated in the accompanying skeleton figures, and may 
be referred to in this way. 
