138 ANATOMY OF THE RABBIT 



thus represents a permanent vaginal process, an outpouching of 

 the peritoneum which in man becomes closed off. 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, i.e., in a position indicating the original 

 situation of the testis itself. 



In the female the ovary is situated close to 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 56 mm., and may be used either in 

 connection with the general features of topography as outHned 

 above, or for the identification of various minor structures appear- 

 ing 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. 



