LEECHFS. 191 



the skin, and is said to cause the most acute agonies, and 

 frequently death. It is found in the marshy districts of 

 Sweden. 



The COMMON HAIR-WORM, is an inhabitant of stagnant 

 waters. It so nearly resembles a horse-hair, that in many 

 places the people believe that it is a horse-hair animated. 

 It has a remarkable habit of twisting itself into fantastic 

 contortions. Its bite has been known to occasion a 

 whitlow. 



The EARTH-WORM is distinguished by a round annulated 

 body, having usually a fleshy belt near its head. Most of 

 the species are rough, with concealed and very minute 

 bristles, placed in lines, and have in the body a lateral 

 opening for respiration. 



The COMMON EARTH-WORM is furnished with a set of 

 muscles which move like a spiral wire about a cylinder, 

 and thus it advances or recedes. It is a mistaken notion 

 that these animals are prejudicial to vegetation ; ort the 

 contrary, by lightening and enriching the soil, they very 

 much promote it. The ravages ascribed to them are 

 committed by the garden slug, and the larvce of insects. 

 The worm, though destitute of brain and eyes, avoids its 

 enemies with great dexterity. During the winter the 

 worms retire into the ground to avoid being frozen, but 

 do not become torpid. 



THE LEECH. 



The animals of the genus HIRUDO, LEECH, have the 

 body oblong and truncated ; their structure is cartilaginous, 

 and they move by dilating the head and tail, and contract- 

 ing themselves into the form of an arch. 



Some species are viviparous ; some deposit their eggs 

 on aquatic plants, and others carry them under their own 

 belly. Several animals proceed from one single egg; 

 some of the smaller species may be multiplied by division. 



The MEDICINAL LEECH is found in stagnant ponds and 

 ditches ; its colour is of an, olive black, and it is marked 

 with six yellowish lines above, and spots of the same colour 

 below; it is about two or three inches in length. The tail 

 is furnished with a circular sucker, and the mouth is armed 

 with three teeth, which leave a triangular mark where 

 they have bitten. This leech is viviparous, producing one 

 young at a time. 



