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, i.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 wav. 



