MOXCECIA — CRYPTOPHALLIA. 
355 
combination, shown by the reten- 
tion of the permanently projecting 
male copulatory organ, distinguish- 
ing other Streptoneures, Valmta 
not having acquired the retractile 
penis characteristic of most herma- 
phrodite species. 
The Cryptophalli A (kpvttto^, 
hidden ; ^aAAos, penis) are charac- 
terized by the possession of a 
male conjugatory organ, which is 
suiTounded or enclosed by a pro- 
tecting sheath completely retractile 
within the body cavity, and also 
exhibiting a great accession and 
complexity of accessory organs. 
The Ciyptophallia in accordance 
with the separation or comhination of the apertures of the male and 
female system of organs, may be subdivided into two groups : 
Ditremata and Monotremata. 
Fig. 6i8. — Reproductive organs of yaivata 
x4(after Bernard), illustra- 
ting the Monoeciate Exophallia. 
ot. ovotestis ; k.d. hermaphrodite duct ; /r. 
prostate ; v.d. vas deferens ; p. penis ; a7>. o\'i 
duct ; c.p. copulatory pouch or sperinatheca 
the uterus of Pelseneer ; a.g. albumen gland 
the spermatheca of Pelseneer; ac.gl. acces 
sory shell gland, the albumen gland of Pel 
seneer \/.o, female orifice. 
The Ditremata (Si'oj, two ; Tpqp-a., 
cavity) comprise the Limnceidcc 
and Carychiidce and are charac- 
terized by the marked separation 
of the male and female orifices ; 
the male aperture is placed beneath 
the tentacle upon the right side of 
the neck in the dextral species, 
and on the left side in those sinis- 
trally coiled ; the female aperture 
being situated beneath the mantle- 
flap in the pallial region on the 
same side of the body but com- 
paratively remote from the male 
aperture. 
This position of the female 
genital aperture is a survival of 
the archaic arrangement found in 
some of the Diotocardia in which 
Fig. 649. — Reproductive organs of Zzwwtf'a 
stagnalis (L.), x2, illustrating the Monceciate 
Ditremata. 
ovt. ovotestis ; pr. prostate ; v.d. vas 
deferens ; p. penis ; ret. penis retractors ; 
p.s, penis sheath with its protractors ; >n.a. 
male aperture ; alb.gl. albumen gland ; n.gl. 
nidamental gland ; ut. uterus ; ero. oviduct ; 
sp. spermatheca ; vag. vagina ; f.o. female 
orifice. 
