SPIDERS. 265 



customary to say the common Earth-worm, but there 

 are several 'which the naturalist knows how to dis- 

 tinguish the one from the other. Montpellier has 

 determined thirty-five species, in Britain the number 

 has been fixed at eleven. The late Dr. Baird gave 

 some interesting details of the habits of worms. He 

 says, " The Earth-worm l moves along the surface, or 

 in the soil, by alternate elongations and contractions 

 of a determinate portion of the body. It can move 

 backwards or forwards with nearly equal facility, and 

 when seized in its progress it wriggles and twists 

 itself into many coiled knots and circles. This it 

 does also -when wounded, and its writhings surely 

 indicate a severe degree of suffering in the poor 

 worm, which is too often wantonly trodden upon. 

 The movements of the earth-worm in its burrow are 

 performed with much greater rapidity than on the 

 surface, a superiority which results from the dis- 

 position of the bristles along the sides for in a cir 

 cular tube alone can they all be brought into action 

 and made to act as fulcra, the animal having the 

 power of protruding them to a slight extent. Hence 

 we find that the hole of the worm is of the same 

 figure as its body, and nearly of the same calibre ; 

 that the ascent and descent may be retarded neither 

 by over straightness, nor by a wideness which would 

 render the contact of the bristles against its walls 

 impossible. The holes are in general sinuous, and 

 worked in an oblique direction, and lined with the 

 slimy juice which exudes from the skin, They vary 



1 Lumbricus terrestris. 



