47 
The mantle is trifid at the base of the pillar lip^ and at the upper 
corner of the aperture ; deposits eggs the beginning of May ; eggs 
enveloped by a transparent gelatinous substance ; the nucleus^ after 
a few days^ appears of a pale or milk white color, and not so well 
defined as those of L. catascopium. 
Paludina subcarinata.* — Shell with three - whorls, which 
are rounded, and subcarinated, reticulated with striae and wrinkles, 
sometimes without the strim ; suture deeply impressed ^ apex trun- 
cated and re-entering • aperture more than half of the length of the 
shell, oval ] elevated lines or subcarina on the body two, three, and 
sometimes none. Length half of an inch ; breadth four-tenths. 
Inhabits with the preceding species. Plate 1, fig. 7. 
Animal viviparous, with a chestnut, coriaceous operculum, white, 
spotted with orange ] head pale orange, not extending beyond the 
shell ; tentacula darker, short, subulate ; eyes situated at their base, 
elevated, black and conspicuous ; base of the animal much ad- 
vanced, broad, truncate, purplish before, tail rounded behind. 
Paludina Virginica.* — Shell tapering, olive, horn color or 
blackish, under the epidermis tinged with green ; whorls seven? 
but little rounded, crossed by curved wrinkles on the spire, and le- 
clivate ones on the body ; a dull red line revolves near the base of 
the whorls, and on the middle of the body a reddish-black broader 
line, from within the upper angle of the aperture, runs parallel with 
the other, and terminates near the base. Aperture subovate, mbre 
than one-third as long as the shell, lip not thickened, but dilated 
at the base. Length one inch ; breadth two-fifths of an inch. 
Plate 2, fig. 4. 
Lister’s Conch, tab. lVj,Jig. 7. The basilar part of the lip in 
Lister’s figure is deficient. 
Inhabitant bluish-white beneath, with orange clouds each side 
of the mouth ; above pale orange, shaded with dusky and banded 
with numerous black interrupted lines ; mouth advanced into a 
rostrum as long as the tentacula, which are darker at the base, and 
setaceous ; base of the animal with an undulated outline. 
It often occurs in our rivers, and is readily discoverable in clear 
water, by the channel it forms in the mud. 
*[In the earlier editions of Nidi. Enc. this species was described iinder 
Lymnaea. — Ed.] 
