THE LAND SNAILS HELICES - FAMILY HELICIDAE. Shell a well developed spiral; lip smooth, or drawn in by a row of teeth: animal withdraws wholly into shell; jaw strong, usually orange-coloured, coarsely or finely ridged; central tooth of radula tricuspid; laterals, tricuspid or bicuspid; marginals usually wider than high, short, with two or three small cusps. Sexes united, but cross-fertilisation is necessary. A family of few genera and a multitude of species, all air breathers, and ter restrial, distributed all over the world.
The study given by conchologists to this great group of shells during the past few decades well illustrates the passing of the conchologist from the cabinet to the laboratory. I would better say back and forth between them. At first the shell alone was the basis of classification. But here is a variable family. Shells of the same species show very different coloration and markings. The study of the jaw became the basis for a new system of classi fication. But the jaw was found to be an unstable character. Shell and jaw alone lead to an artificial system of classification, and do not help to solve the problems of origin and relationship of species. Studies of the anatomy of the soft parts have thrown much light upon the subject.
The assembling of the species of Helices filled eight volumes of the "Manual of Conchology." In Volume IX. Pilsbry dis cards the older classification and declares for a new, natural system based upon the development of the shells and of several unrelated sets of internal organs. The genitalia and dentition are emphasised.
Under the new classification the Helices are reduced to about fifty genera. Of these the largest and most beautiful are tropical. The United States has representatives of several genera — our common land snails, dull in colour and of small size. The Philip pines, Mauritius and the East and West Indian Islands have the showiest forms, the handsomest of which live in trees. Ground 256 The Land Snails. Helices snails are always dull-hued. One of the largest is a brindle banded snail, H. Falkneri, Rve., four inches in diameter, from New Holland.
Genus HELIX, Linn.
Shell solid, globose or depressed; whorls about five, rounded or keeled; surface ribbed or granulated, plain, with spiral bands, usually five or fewer; lip expanded, reflexed or thickened. Man
tle tough, granulose, grooved along back with side lappets, left long, right short. Sole undivided; tail depressed; jaw and radula well developed; reproductive system highly complex. Found in temperate and tropical countries.
In spite of the eliminations made by Mr. Pilsbry from Lin nxus's overburdened genus Helix, it still includes so large and so varied an assemblage of species that it is a hard matter to bound it. It is the most highly organised genus of snails. Naturally inhabiting wooded regions, yet these mollusks take kindly to life in the open, in striking contrast to our native snails which are largely destroyed with the laying waste of their forest homes.
Helix, lover of the sunshine, well deserves its name. Its cheerfulness under radical changes of climate and conditions of soil and food are a source of amazement to scientists. It is native to the mild regions around the Mediterranpan Sea. North Africans, the people of Asia Minor, and of Southern Europe, all hold snails in high esteem as in article of diet, and have from the earliest times. In scattering to the western hemisphere these people have taken snails with them wherever they went; and these molluscan colonies have succeeded — in South America and North. The Roman soldiers probably took their favourite Helix with them when Cxsar invaded Britain in 56 B. c. So certain authorities hold, for colonies of Helix still exist near the sites of the old castra, built by Cxsar's soldiers.
The poorer classes in England consume snails in quantities each year. It is a common sight on the crowded thoroughfares to see a hungry person stop at a little charcoal pot and buy a penny's worth of hot boiled or roasted snails. These he picks out of their shells with a pin and eats them as he goes along. This is the brown-lipped woods snail (H. nemoralis), which White of Selbourne says is the favourite food of the song thrush. The 257 The Land Snails. Helices bird breaks the shell by repeated strokes upon a stone; particular stones are selected and resorted to regularly, as is proved by the heaps of broken shells around them.