Home › Volumes › Shells › Univalves and Chitons

Family Helicidae — Part 3

Genus BULIMUS, Scop.

SHELL spiral, ovate-oblong, solid, whorls few, the last one ventricose and large; aperture elongated; columella wide; lip thick, turned back. Animal like Helix; jaw simple, ribbed. Tropical America.

The Ovate Bulimus (B. ovatus, Mull.) attains the length of six inches, and except Achatina, is the largest known land snail. The Negroes of Rio Janeiro buy it as a shell fish in the markets, and consider it a delicacy. The eggs are white and hard-shelled, and so large that one might easily mistake them for pigeons' eggs. The mollusk lays them (not many) in a rude nest dug in the ground and loosely covered with dead leaves. The eggs, too, are used as food.

The shell is ovate, with prolonged spire, and has the nondescript, streaked, horny colour calculated to conceal it from detection among dead grass blades.

Habitat.-Forests of Brazil.

Many smaller species are brightly painted, and have curiously exaggerated lip expansions, inside and out.

Sub-Genus STROPHOCHEILUS, Spix

The thick-lipped S. scarabus, Alb., has a pointed ovate spire, with brown epidermis covering the white shell substance. The peristome is simple, surrounding the ear-shaped or oval aperture. The largest specimens are four to five inches long, and come from New Caledonia.

There are African and Brazilian species.

Genus BULIMULUS, Leach

Shell oblong, aperture longitudinal, lip thin. About six hundred species. Tropical America. Several Mexican species invade Texas and other Southern states.

B. multilineatus, Say, with its seven yellow whorls wound with varying bands of brown, ranges from New Granada to the coasts of Florida. Length, 1 inch.

B. alternatus, has irregular pale brown and drab longitudinal bands traversing its spire. The white lip has a tooth folded back over the columella. This Mexican species is abundant on bushes in Texas. Dead shells often cover the ground beneath. Length, 1 1/2 inches,.

Buliminus, Ehrenb., is a large Old World genus corresponding to the New World Bulimulus.

Mr. Layard, an English field naturalist, who explored the Comoro Islands, west of Africa, in 1854, writes:

One day I took refuge from a shower of rain under a bushy tree creeper. I observed that the branches were covered with short, stout spines. As the rain ran down the branches I was astonished to see some of the "spines" move along the bark! On taking them in my hand I was pleased to find that they were Bulimini! They were covered with a thick, scurvy epidermis exactly like the spines of the creeper.

Here is a fine instance of protective mimicry.

Genus BINNEYA, Coop.

Animal slug-like, blunt before, tapering behind; shell central, of few coils, ear-shaped, covering the mantle, but not the body; jaw and radula prominent. The shell contains the coiled visceral parts. The foot is free and unprotected by the shell.

B. notabilis, Coop., a Mexican species, wears its tiny, ear-shaped, horny shell as a collegiate youth does his "ingrowing" cap. In the hot summer this slug-like mollusk clothes its soft body in a papery chrysalis attached to the shell. Length, 1/4 to 1/2 inch.

Habitat.-Santa Barbara Islands.