PULMONATA. 7 



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 

 except during twilight or on damp and dark days ; indeed, they 

 almost entirely 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 Helix alternata 

 and H. varians, Achatina fasciata, &c., there is scarcely a 

 species having bands or variegated colors inhabiting eastern 

 North America; and even there these latter species can scarcely 

 be regarded as an exception, as they are only to be found at the 

 southern part of Florida, and are more properly West India 

 shells. In Texas, and beyond 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 desig- 

 nated by Ferussac under the name Helicodonta. More than one- 

 half of the whole number, and more than three-fourths of those 

 with reflected lips, are thus provided. In some species these 

 appendages assume the form of folds rather than teeth ; and in 

 others we have simple threads or laminss revolving within the 

 aperture in the course of the spire. They are not formed until 

 the shell has attained its full growth. 



The genera not furnished with an external shell were grouped 

 into one family of Limacidee by Binney, who thus describes their 

 habits : They are more especially nocturnal than the other families 

 of the order, and they are so rarely visible in the daytime that 

 thousands may be near without being known. The injury which 

 they commit in kitchen-gardens, for this reason, is often vaguely 

 ascribed to worms or to birds ; and no measures are taken against 

 the real culprits. Their habits, in general, coincide with those 

 which have been described as distinguishing the order ; and we 

 shall therefore mention here only those which are peculiar to 

 them. They differ from the other families in not possessing the 

 faculty of hibernation, or suspension of their organic functions 

 during the cold season. In temperate latitudes, the snails hiber- 



