310 



LOWER INVERTEBRATES. 



what constitutes a family here is not yet settled. We have endeavored to take a con- 

 servative course in this respect, and hence but few families represent the many divi- 

 sions which exist in some systems. The first is the Testacellid^, in which the animal 

 is like the familiar garden slug, but bears a small shell on the hinder end of the body, 

 and the mouth has no upper jaw. The genus Testacella is European and is noticeable 

 from the fact that it forms an exception to the other pulmonates in being predatory 



and carnivorous. Its prin- 

 cipal diet is earth-woims. 

 It lives beneath the surface 

 of the earth, and follows 

 the worms down their bur- 

 rows. Other articles of food 

 are snails and slugs, and it 

 wUl even eat its own spe- 

 cies. It, however, wants its 

 prey alive, and even refuses 

 pieces of a fresh worm which 

 has been chojiped up to feed 

 it. Many tales are told of 

 its ferocity and cunning. They are said to live for five or six years ; at the approach 

 of cold weather they burrow deep into the earth, and, with the mucus they secrete, 

 they form a cocoon in which they spend the winter. 



Allied to Testacella, but still entitled to family rank, is a group which is called 

 OleacinidjE. As in the last family, an upper jaw is wanting, but the shell is much 

 better developed and capable of containing the body when retracted. Most prom- 

 inent is the genus Glandina, with about a hundred and twenty-five species. It has a 

 fusiform shell with a thin, sharp, outer lip. Glandina truncata, our best known species, 

 extends from South Carolina to Texas, and possibly further south. It prefers moist 

 situations, and thrives in the Everglades of Florida, living in humps of coarse grass. It 

 is partially if not wholly carnivorous, but, unlike Testacella, it is not averse to dead 

 animal matter, and will eat that which is partially decajed. It is even cannibalistic. 

 Its tongue is armed with numerous long, sharp teeth, with which it rasps off large 

 mouthfnls of its prey. The shell is usually ashy fawn color, more or less tinged with 

 pink, which soon fades after death. In a Central American species, G. rosea, the 

 color persists to a much greater extent. Some of the South American species are 

 much more predacious than our forms, and do not hesitate to attack snails as large 

 or larger than themselves. 



In Streptaxis, a South American genus, the shell is more like that of the normal 

 species of Helix (to be described below), but there is a curious distortion. The axis 

 of the shell is bent so that the lower whorls are not parallel to the earlier ones. 



The American family CYLiNDEELLiDiB needs but a passing mention. The shell, as 

 the name indicates, is shaped like a cylinder, composed of many whorls, the last being 

 usually more or less detached from the others, and terminated by a circular mouth. 

 The animals have sluggish motions, and drag their shell horizontally behind them. A 

 few species are found in Florida, but the family reaches its highest development in 

 the tropics, especially in the West India Islands. 



The Helicid^ is by far the largest family of pulmonates ; indeed, it contains more 

 species than all the other families together. Over sixty-five hundred species have 



