20 



THE MUSEUM. 



be eaten, the semi-lunar rough instru- 

 ment, usually called the "lingual mem- 

 brane," is brought up against it, cut- 

 ting out and carrying into the mouth 

 semi-circular portions of nutriment. 

 The operation is carried on with great 

 rapidity, and the substance to be eaten 

 soon disappears. It is certain, how- 

 ever, that some species are fond of an- 

 imal food, and sometimes prey upon 

 earth-worms, their own eggs, and even 

 upon each other; but the slowness of 

 their motions and their consequent in- 

 ability to pursue prey, forbids the idea 

 of their being dependent upon animal 

 food. They, in their turn, become 

 the prey of various birds and reptiles; 

 and it is no uncommon thing to ob- 

 serve, in the forest, clusters of broken 

 shells lying upon logs or stones, which 

 have been chosen by birds as conven- 

 ient places for breaking the shell and 

 extracting the animal. 



The snails of the United States are 

 for the most part solitary in their hab- 

 its, differing very much, in this respect, 

 from the snails of Europe. It is true 

 that in localities favorable for their res- 

 idence they may be collected in con- 

 siderable numbers; and especially is 

 this the case in the states north of the 

 Ohio River. But even there they seem 

 to live independently of each other, 

 and not to unite into herds and com- 

 munities. There are occasional ex- 

 ceptions, however, as in the case of 

 Pyramidula alternata, very large num- 

 bers of which have been observed col- 

 lected into a small space, especially in 

 winter, as if for the purpose of impart- 

 ing warmth to each other. The few 

 species of European snails which have 

 been introduced retain their native 

 habits. Helix hortensis, for instance, 

 which has been transplanted to some 

 of the small islands in the vicinity of 

 Cape Ann, is found there in countless 

 numbers, literally covering the soil and 

 shrubs. It is worthy of notice also 

 that each island is inhabited by a var- 

 iety peculiar to itself, showing that the 

 variety that happened to be introduced 

 there has propogated itself without a 



tendency to run into other variations. 

 Thus, on one islet is found the yellow- 

 ish green unicolored variety, once de- 

 scribed as Helix subglobosa; and on 

 another, within a very short distance, 

 we find a banded variety and none 

 others. 



In regard to colors our snails are 

 quite plain and exceedingly uniform; 

 in this respect also differing essentially 

 from the species of the old world. 

 They vary from yellowish-green, 

 through horn color to chestnut, most of 

 them being simply horn colored. This 

 is perhaps owing to the fact that our 

 species do not infest our gardens and 

 open fields, but are generally confined 

 to forests, sheltered under logs and 

 stones, and are rarely seen abroad ex- 

 cept during twilight or on damp and 

 dark days; indeed, they almost entire- 

 ly disappear as the forests are cut down 

 and seem to flee the approach of man. 

 The European species, on the other 

 hand, follow in the track of cultivation, 

 and are common in gardens and fields, 

 on walls and hedges, and other places 

 exposed to the action of light. With 

 the exception of Pyramidula alternata, 

 Hemitrochus varians, Lignus fasciatus, 

 etc., there is scarcely a species having 

 bands or variegated colors inhabiting 

 eastern North America; and even there 

 these latter species can scarcely be re- 

 garded as an exception, as they are 

 only to be found in the southern part 

 of Florida, and are more properly 

 West Indian shells. In Texas and be- 

 yond the Rocky Mountains in Oregon 

 and California, many of the species 

 have one or more bands. 



Another peculiarity of the American 

 snails, is the tooth-like appendages 

 with which the aperture of a large 

 proportion of them is armed, and 

 which are characteristic of the group 

 designated by Ferussac under the name 

 of Helicodonta. More than one-half 

 of the whole number, and more than 

 three-fourths of those with reflected 

 lips, are thus provided. In some spec- 

 ies these appendages assume the form 

 of folds rather than teeth; and in 



