THE NATURAL HISTORY SURVEY. 353 
form a verge, and very large; eyes situated on peduncles at 
the outer bases of the tentacles. Radula with the formula 
3-1-3; central tooth broad, with rounded edges on base, re- 
flected cusp denticulated; lateral teeth longer than wide, the 
two inner denticulated on their reflected portions; and the 
outer tooth simple or denticulated. 
The genitalia may be thus briefly described: In the male 
the penis is lodged in the right tentacle and is large and cylin- 
drical; the seminal or genital bladder follows, being a very 
large, cylindrical sac, from the end of which extends the vas 
deferens, which terminates in two testicular lobes, one ante- 
rior and one posterior. In the female the ovaries are small 
and digitiform, and lead by a long, narrow oviduct into the 
uterus; at this point the receptaculum seminis and albumin- 
Fia4. 183. 
Animal of VIVIPARA. V.INTERTEXTA Say, Binney, Figs. 30, 31.) Fe- 
male and male. 
iparous gland are placed, both being quite large; the uterus 
is much swollen and gut-like, and opens by a contracted por- 
tion, the vagina. The testes and ovaries are embedded in the 
liver (Fig. 132). 
Genus VIVIPARA Lamarck. 
Shell: With rounded whorls frequently banded; aperture 
ovately rounded; peristome continuous. Operculum annular, 
horny. 
“Animal: With a long muzzle and very short eye-pe- 
duncles; neck with a small lappet on the left side anda larger 
on the right, folded to form a respiratory siphon; gill comb- 
like, single; tongue short; teeth single, oval, slightly hooked 
and denticulated; uncini 3, oblong, denticulated. The Vivipa-° 
vid@ are viviparous, the young continuing for some time after 
they are hatched within the parent shell.” (Tryon).* (Fig. 
133.) 
*S. and S. Conch., Vol. II, p. 274. 
