MOLLUSCA OF INDIA. 231 
widens, giving off several strong cervicorn or more or less branched 
processes, which are directed backwards; they serve, I think, to aid 
in the expulsion of the spermatophore from the penis, and, when 
once within the spermatheca or vagina, serye as holding-hooks to 
prevent its withdrawal. The part above this consists of a very long 
thin membranous bag 0-4 inch long, terminating in a hard conical 
cap, from which proceeds a thin rod, which is found to extend to the 
hard rounded apex of the spermatic sac, where it bends over or ends 
in a few separate filaments within the tube of the vas deferens. In 
one specimen of this species (gigas) no less than seven perfect 
spermatophores were counted, closely packed together side by side 
within the spermatheca. (Van Beneden observed two in a Parma- 
cella, Ann. Sci. Nat. 1857, p. 371.) 
‘“* It would appear that in these creatures even one act of copulation 
would fertilize for a very considerable period ; for it would be some 
time before the contents of a spermatophore became exhausted. 
‘This organ, as situated in the penis, presents the character of a 
perfect spring (vide plate xxvi. figs. 2,3); and it can be imagined 
that when it enters the wider and very elastic sac of the spermatheca, 
and is then gradually released, it will tend to become quite straight, 
and that, the recurved processes holding it at one point, the longer 
portion will bend round to the long axis of the sac, bringing the end 
of the shorter portion (plate xxvi. fig. 3a) to the aperture within 
the vagina and ovo-testis (plate xxvi. fig. 4, 7. sp.). 
‘** Macrochlamys decussata, of which I have a drawing, taken when 
the animals were 7 coitu, protruded a large white bladder-like sac, 
which expanded and contracted from time to time as if inflated with 
air; this I now think may have been the spermatheca drawn out 
and receiving the penis and capreolus. 
“In the two specimens I examined, the spermatheca (sp.) was 
elongate, smooth, lying close to and partly enveloped by the con- 
volutions of the oviduct &ec., with its posterior end near the junction 
of the hermaphrodite-duct and albumen-gland. This posterior 
termination is bent over on itself, presenting a smooth rounded end 
(plate xxv. figs. 2 & 4), which coiling round, terminated, and was 
covered with what was apparently muscular tissue buried in the 
prostate and oviduct. The form of the spermatheca is due to its 
contents ; and the rounded end is produced by the bending-over of 
the flagellum-like terminations of the enclosed spermatophores. 
‘Tn one specimen of G'. hookert which I examined, probably taken 
in the cold weather, all the generative organs are small and con- 
tracted, the spermatheca only represented by an attenuate sae. 
«The amatorial organ or dart-sae (D)* is a long cylindrical body 
narrowing towards the genital aperture, and again swelling there 
into a large orifice ; it has a very thick and muscular structure, and 
in these spirit-specimens is very hard and unyielding. When cut 
open longitudinally, the dart or spiculum amoris was found to be a 
simple cylindrical rod, sharply pointed (plate xxvi. fig. 7). This 
* “Glandula mucosa cum sagitta amatoria.” 
