274 PALUDINIDA. 
Lyoayrus, Gill. (Heterocyclus, Crosse.) Spire elevated, the 
last whorl becoming detached from the close spiral near the 
aperture. U.S., New Caledonia. V. pupoidea, Gould (Lxxiii, 100). 
Famity PALUDINID. 
Shell conical or globular, with a thick, olive-green epidermis ; 
aperture rounded; peristome continuous, entire. Operculum 
horny. 
Animal with a broad entire muzzle; tentacles short and rather 
stout ; eyes on short pedicels, outside the tentacles. Inhabiting 
fresh waters in all parts of the world. Dentition (xi, 25). 
Patupina, Lam. 
River-snail. Htym.—Palus (paludis), a marsh, 
Syn.—Vivipara, Montf. Viviparella, Raf. 
Distr.—100 sp. Fresh water, mostly in the Northern hemi- 
sphere, Australia.* Fossil, 75 sp. World-wide. Jurassic—. 
P. Bengalensis, Lam. (1xxiv, 6). 
Shell turbinated, with round whorls; aperture slightly angular 
behind ; peristome continuous, entire. Operculum horny, con- 
centric. Animal with a long muzzle,and very short eye-pedicels ; 
neek 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 denticu- 
lated; uncini 8, oblong, denticulated, The Paludine are vivi- 
parous; the young continuing for some time after they are 
hatched within the parent shell. 
PALUDINA (restricted). Whorls rounded, generally banded, 
rather thin, umbilicated. The European species have three 
bands, those of the United States four bands, whilst the nu- 
merously banded species are Oriental. 
MELANTHO, Bowdich. Whorls smooth, flattened around their 
upper portion, generally not banded, solid, nearly or quite 
imperforate. Peculiar to the United States, P. integra, Say 
(baxiv, 1: 
TULOTOMA, Hald. Whorls angulated, nodulous, flattened 
around their upper portion. P. bimonilifera, Lea (1xxiv, 8). 
MARGARYA, Nevill. Spire produced; whorls scalariform, with — 
deep suture, sculptured with prominent spiral ribs; apex obtuse ; 
rimate. Operculum and animal unknown. Distr.—P. Melan- 
oides, Nevill (Ixxiv, 9). Lake Tali, Yunnan. Closely allied to 
the American subgenus Tulotoma. 
NEOTHAUMA, EK. A. Smith. Shell with aperture effuse and 
slightly channeled at the base; outer lip rather deeply, yet 


* There are no So. American species, norin N, Am. west of the Rocky 
Mountains. 
