The Black Snails - Marsh Snails - Family Melaniidae

THE BLACK SNAILS - MARSH SNAILS - FAMILY MELANIIDAE Shell spiral, turreted; spire often worn; epidermis dark, thick; aperture notched or chambered in front; outer lip sharp; operculum horny, spiral.

Animal with broad, short, foot; broad, non-retractile snout; tentacles far apart, bearing short eyestalks; tongue long, slim, with seven series of many-cusped teeth; mantle margin fringed; gill of stiff, cylindrical plates. Reproduction A large family inhabiting fresh water lakes and rivers, in warm regions, chiefly of the Old World.

Genus MELANIA, Lam.

Shell with

acute apex, its whorls ornamented with spines or striations; aperture oval, pointed above. Four hundred species, distributed over Southern Europe, India, Philippines, Pacific Islands, in swift tidal rivers, especially in rapids.

The Melanias include forms with cancellated, tubercled and smooth shells. They range from globose to needle-like forms. The largest is under three inches long. Many species have their shells decollated — broken off at the apex. The finest species are Philippine.

The Acorn Black Snail (M. glans, Busch) is smooth, oval, olive-hued, with a depressed spire; the body whorl and the aperture are both very large. Length, I inch.

Habitat.— Java, Philippines.

The Bristly Black Snail (M. setosa, Swains.) is globose and has its spire set with a spiral row of erect sharp spines. The black or green exterior contrasts with the pale lip and throat. Length,

I inches.

Habitat.— Philippines, Fiji Islands.

M. hastula, Lea,

is fawn-coloured and long and tapering 184 The Black Snails. Marsh Snails like the auger shells. Its whorls are few, cross-ribbed and some what rounded. Length, 2 to 3 inches.

Philippine

s.

M. lxvissima,

Sby., is a solid, stout, smooth, conical shell, thick-lipped, ashy blue streaked with purple. Length, 1 to 2 inches.

Habitat.— Mexico.

Genus PALUDOMUS, Swains.

Shell conical or globose; aperture large, round; peristome continuous; columella callous; operculum spiral; animal like Melania. Twenty-five species, found in India and Ceylon.

Gardner's Paludomus

(P. Gardneri, Rve.) is the most characteristic species. The orbicular-ovate shell is deeply sculp tured by blunt, spiral ridges, alternately large and small; the mouth is large, the spire depressed; colours, black outside, white inside, with purple-stained lips. Length, 1 inches.

Habitat.— Ceylon.

The Paludomus (P- loricatus, Rye.) is a stony, globose shell, wide mouthed like a Nerite, which it otherwise closely resembles. The revolving ribs are set with triangular points, like diminutive shark's teeth. The brown exterior con trasts sharply with the white interior. Length, ti inches.

Habitat.— Ceylon.

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