PERITONEAL RELATIONS OF THE MAMMALIAN OVARY. 37 



respectively to the posterior and anterior portions of the ovarian 

 ligament, described by Owen in the Ornithorhynchus.* 



Both strands give rise to reduplications of the mesial layer of the 

 broad ligament; and between these reduplications, together with 

 the ovary on the inner side, and the broad ligament on the outer 

 side, the peritoneum is depressed into a shallow pouch, the mouth 

 of which is widely open ventrally. This pouch may become de- 

 veloped into a distinct sac, and it will be convenient to speak of it 

 afterwards as the " ovarian sac." 



The outer wall of the sac is greater in vertical height than the 

 inner, usually exceeding it to such an extent that the free edge of 

 the ovary, which projects beyond the inner edge of the sac, is on a 

 level with the free edge of the broad ligament. 



The relations of the Fallopian tube and its abdominal orifice to 

 the sac are of considerable importance, and it becomes necessary 

 therefore to consider their position carefully. 



The Fallopian tube is found to be placed between the layers of 

 the broad ligament, usually a little dorsal to its free edge, though 

 in many cases, and among others the human female, the cat, and 

 the tiger, it occupies the free edge of the ligament. It is, however, 

 always placed in the outer wall of the sac. Its orifice is situated 

 either on the inner face of the outer wall of the sac, from which it 

 projects slightly, or on the free edge of the broad ligament, from 

 which it also projects. The abdominal termination of the oviduct 

 is funnel-shaped ; the funnel is compressed from above downwards, 

 consequently the orifice is an elongated slit. The anterior extremity 

 of this slit is attached to the anterior extremity of the ovary ; the 

 posterior extremity remains free. The orifice lies on the outer edge 

 of the sac, and is parallel with the ovary. This simple form of sac 

 is of common occurrence, and it has been described and figured by 

 various anatomists. It is met with in Hycena crocuta,\ in the rabbit, 

 cat, tiger, &c. It becomes modified and rendered more distinct in 

 the following manner : — The Fallopian tube becomes elongated, its 

 orifice being fixed, the tube is pushed forward between the layers of 

 the broad ligament, and becomes folded on itself. This increase in 

 length of the Fallopian tube is accompanied by a simultaneous 



* Loc. cit., vol. iii., [). 077. 



t M. Watson, Proc. Zool. Hoc, May 1, 1877, p. '612. 



