The Pond Snails - River Snails - Family Viviparidie Paludinidae

THE POND SNAILS - RIVER SNAILS - FAMILY VIVIPARIDIE (PALUDINIDAE).

Shell

turban-shaped; aperture simple; lip continuous; epidermis olivaceous; operculum annular; foot large; snout short, stout; right tentacle enlarged in male; eyes on base of tentacles; teeth broad, serrated. Animal ovoviviparous.

Genus VIVIPARA, Lam.

Shell thin; spire produced; surface smooth; body dark; head large; foot thick, not extending beyond the moderate snout; neck lappets forming troughs to admit and discharge water from the gill chamber.

V. intertexta,

Say, is globular, with three or four yellowish green or brownish whorls; the elevated apex is worn at the tip; the lines on the surface are but skin deep. Lip continuous and white. Maximum length and breadth, I inch.

Habitat.— Marshes of Louisiana.

Mr. Binney received specimens from Iowa and South Carolina.

V. multicarinata,

Hald., bears distinct raised revolving and cross lines, on the green conical shell. The mouth is round and large. Length, I I- inches. Southern states.

V. contectoides,

Binney, has five greenish rounded coils forming a tall spire, and ending in a round mouth. Cross streaks intersect the four revolving bands of brown which show through the thin shell substance. A variable and handsome species, allied to the European, V . contecta. Length, I inch.

Habitat.— Michigan and Arkansas to Florida.

Mr. Maxwell Smith has recently found Vivipara in locks of the Erie Canal at Rochester, N. Y.

Genus TULOTOMA, Hald.

The Magnificent Tulotoma (T. magnifica, Conr.) is a solid conical shell with two spiral rows of tubercles on the body whorl, 195 The Pond Snails. River Snails

and a single row winding to the truncated apex. This shell is the handsomest in the family. It is found on masses of crumbling limestone fallen from the river banks. The greenish epidermis contrasts pleasingly with the rich purple or salmon colour of the smooth lining. Height, t to 2 inches.

Habitat.— Alabama River at Claiborne.

Genus MELANTHO, Bowditch Shell ovate; spire elevated; whorls rounded, smooth; peristome continuous, simple; epidermis olive; foot large, thin, protruding much beyond the small snout; flesh pale, red-dotted; teeth small.

The Heavy Melantho (M. ponderosa, Say), typifies the genus. The inner lip is applied as a thickening fold to the colu mella. Dark streaks are painted on the greenish exterior. The lining is white; so is the surface under the horny epidermis. The animal has a curious habit of flattening the foot and curling it outward into a thin scroll, square in front, The neck lappets are not grooved as water ducts. Length, t to 2 inches.

Habitat.— Lake Superior to Alabama.

Genus LIOPLAX, Troschel Shell thin, ovate; spire elongated; foot large, square in front, rounded behind, projecting beyond small head. A few species in the United States. Variable.

L. subcarinata,

Say, has three rounded whorls, smooth or showing a few faint elevated revolving lines. The apex is often worn; the aperture oval. The foot is purplish in front, the head pale orange, the eyes black. Length, inch. Habitat.— Delaware River.