1 OVIDUCT VE 
It is the general rule amone vertebrate animals that the 
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 a general rule. But in 
quite a number of 
forms folds of the 
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. the 
ovaries. The ovi- 
duct, moreover, has 
a large and fimbri- 7, : \ 
ated mouth, called Jt rut 
in human anatomy Fic. 47.—Lepus cuniculus. The anterior end of the vagina, 
; : : with the right uterus, Fallopian tube, and ovary. (Nat. 
—which is provided size.) Part of the ventral wall of the vagina is removed, 
oH ; r > and the proximal ‘end of the left uterus is shown in 
with a number of ioneeiainall section. jl.¢, Fallopian tube ; 71.1’, its peri- 
fanciful names — toneal aperture ; /.ut, left uterus ; ut’, left os uteri ; 
ov, ovary ; r.ut, right uterus ; 7.ut’, right os uteri; s, 
the morsus diaboli. vaginal septum ; va, vagina. (From Parker’s Zootomy.) 
This almost wraps 
round the ovary, and thus prevents the ova from straying in 
the wrong direction. Moreover, the ovary itself is often so 
arranged that it can easily be withdrawn into a pocket of 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.2 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 
1 Robinson, Studies Biol. Lab. Owens Coll. ii. 1890, p. 35. 
? Beddard, Proc. Zool. Soc. 1900, p. 667. 
