8 LIMACID^E. 



They possess, in a remarkable degree, the power of 

 elongation and contraction of the body. When fully ex- 

 tended 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 tentacles are long, slender, 

 and graceful. The mouth is changed from an oval to an 

 elongated form, with parallel sides and rounded ends. 

 The glands are lengthened, lose their prominence, 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 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 centre, and the 

 skin is rough with prominent glandular protuberances. 

 The carina, when it exists, becomes conspicuous. This 

 is the form which they assume in their retreats 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 



