KEPRODUCTIVE SYSTEM — HERMAPHRODITE DUCT, ETC. 
359 
aspect and arrangement, and usually lie within the body cavity, 
between the lobes of the digestive gland, with which its parts may be 
intimately intermingled. In the Pelecypoda the paired gonads are 
usually richly branched tubular or lobate masses, often occupying the 
base of the visceral mass and permeating amongst the intestinal coils. 
The Hermaphrodite Duct (‘iS'pp]?, Mercury ; A<Ppo8lti], Venus) 
the conjoint canal of the ova and semen, is only found in the monoe- 
cious species, originating at the ovotestis or hermaphrodite gland, 
and terminating in the seminal vesicle at the base of the albumen 
gland ; its swollen part is the epididymis of continental authors, but 
the duct is very variable in its character and extent, it may be 
voluminous, sinuously convoluted and deeply pigmented as in Suc- 
cinea, simple and nearly straight as in Hyalinia, or beset with 
numerous glandules along the greater part of its course as in many 
of the Limnceidce. 
The Seminal Vesicle {semen, seed; veskula,A\m. of m’/ca, a bladder) 
or Claw, known also as the Epididymic coecum, is a variously formed 
coecal diverticulum, situate at the base 
of the concave side of the albumen 
gland, to which it is closely apposed ; 
it is sometimes constituted by a mere 
swollen convolute termination of the 
hermaphrodite duct, or, as in Succinea, 
may be paired, and open with the albu- 
men gland into a fertilizing cavity, but 
in some species beneath the point 
where the swollen portion is imbedded 
in the albumen gland there is a lateral 
tube bearing several blind ramifying 
tubules lined with ciliate uugranulated 
epithelium, which is lodged between 
the ascending and the swollen de- 
scending part of the efferent canal and in the adult contain living 
spermatozoa which fertilize the ova before passing within the saccu- 
lated and glandular oviduct. 
The Albumen Gland {album, white) is an adjunct of the female 
system, and is a light-coloured linguiform organ, convex behind 
and concave in front, where the hermaphrodite duct terminates 
in the seminal vesicle. The gland is very slightly adherent to the 
Fig. 655 , — Succinea elegans Risso, x 6, 
showing the character and relationship of 
the pigmented hermaphrodite duct, the 
paired seminal vesicles, the albumen 
gland, and the ovotestis. 
a.g, albumen gland ; k.d. hermaphro- 
dite duct ; ot. ovotestis ; v.s, seminal 
vesicles. 
