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- 



FIG. 133. 



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 and a 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- 

 rid(B 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. 



