A MANUAL 01 AMERICAN LAND SHELLS. 17 



They possess, in a remarkable degree, the power of elongation and 

 contraction of the body. When fully extended it is long, narrow, more 

 or less cylindrical, and generally terminating in a sharp point. The 

 carina of the carinated species disappears. The head is protruded far 

 beyond the mouth*; the eye-peduncles are long, slender, and graceful. 

 The mantle is changed from an oval to an elongated form, with parallel 

 sides and rounded euds. The glands are lengthened, lose their promi- 

 nence, and appear nearly smooth. But when alarmed by the touch of a 

 foreign substance, an instant change occurs, and a sudden contraction 

 takes place. The eye-peduncles and tentacles are retracted and the 

 head is drawn under the mantle. The anterior edge of the mantle is 

 brought to the level of the foot, and its form becomes nearly circular. 

 The body is shortened to one-fourth of its former length, and tumid; 

 the back is rounded and rises high in the center, and the skin is rough 

 with prominent glandular protuberances. The carina, when it exists, 

 becomes conspicuous. This is the form wMch they assume *in their re- 

 treats when they retire to protect themselves from the effects of drought 

 and cold. It differs so much from their form when in motion, that one 

 not well acquainted with them would hardly recognize the same animal 

 in its new shape. It is among the Limaces, perhaps, that the change is 

 most striking and the difference of form between the extremes the 

 greatest. 



They commence reproducing their kind as early as the end of the first 

 year, before they have attained their full dimensions, and hence the 

 eggs of the same species often vary considerably in size . These are 

 deposited in a cluster of thirty, or thereabouts, in the soil and in other 

 moist and protected situations ; or if the species be one that frequents 

 houses, then in the crevices or corners of the walls or under the decay- 

 ing planks of cellars. In general form and appearance they resemble 

 the eggs of the shell-bearing genera, but differ from them in several im- 

 portant particulars. The eggs of the snails are all opaque, while those 

 of the slugs are more or less transparent, permitting in the Limaces a view 

 of the cicatricula, and affording an opi^ortunity of observing its devel- 

 opments. Those of the former are all deposited free, or unconnected, 

 except by a slight agglutination; those of the latter, in some of the spe- 

 cies, are connected together by a prolongation of the outer membrane at 

 their longer diameter, thus forming a sort of rosary. The deposits of 



eggs, when made; are abandoned by the slug, which then removes to some 

 1749— BuU. 28—2 



