OVIDUCT 



73 



o-eneral rule. But in 



l.Tlt 



It is the general rule among vertebrate animals that tlic 

 ovaries are completely independent of the ducts which convey 

 their products to the exterior. In certain fishes, however, there 

 is an absolute continuity between the two structures, which is 

 believed to be due to a. simple concrescence between the originally 

 distinct ovary and oviduct. The latter has grown round the 

 former, an obvious advantage in preventing the eggs from 

 wandering into the abdominal cavity and becoming lost. In 

 the Mammalia we find discontinuity as 

 quite a number of 

 forms folds of the jjl^ 



lining membrane of 

 the abdominal cavity 

 are developed, which 

 practically ensure 

 the passage of the 

 ova into the ovi- 

 duct when they are 

 extruded from tlie 

 ovaries. The ovi- 

 duct, moreover, has 

 a large and fiml ab- 

 ated mouth, called 

 in human anatomy 

 — which is provided 

 with a number of 

 fanciful names — 

 the morsus diaboli. 

 This almost wraps 

 round the ovary, and 

 the wrong direction, 

 arranged that it can 



Fig. 47. — Leptis cmiicvlus. The anterior end nl' the vagina., 

 with the right uterus, Fallopian tn1)e, and ovary. (Nat. 

 size.) Part of the ventral wall of the vagina is removed, 

 and the proximal end of the left uterus is shown in 

 longitudinal section. Jt.t, Fallopian tube ; fl.t', its peri- 

 toneal aperture ; l.ut, left nterus ; l.ut', left os uteri ; 

 ov, ovary ; r.ut, right utervis ; r.ut', right os \iteri ; .v, 

 vaginal septum ; va, vagina. (From Parker's Zonlomj/.) 



thus prevents the ova from straying in 

 Moreover, the ovary itself is often so 



easily be withdrawn into a pocket of 

 the peritoneum, from which the obvious exit is by the gaping 

 mouth of the oviduct. This disposition of the generative parts 

 is still further modified in a few animals, such as the Rat^ and 

 the Kinkajou.'^ In these animals the mouth of the oviduct 

 actually opens into the interior of a closed chamber which con- 

 tains the ovary. In this case there is but one route for the 



^ Rol)insoii, Studies Biol. Lah. Oivens Coll. ii. 1890, p. 35. 

 - Beddard, Proc. Zool. Soc. 1900, p. 667. 



