LEACH. 173 



HiRUDo. — The Leach. 



The Medicinal Leech, which is well 

 kjiown, grows to the length of two or three 

 inches. The body is of a blackish brown 

 colour, marked on the back with six yellow 

 spots, and edged with a yellow line on each 

 side : but both the spots and the lines grow 

 faint, and almost disappear, at some seasons. 

 The head is smaller than the tail, which 

 fixes itself very firmly to any thing the 

 creature pleases. — The geometrical Leech 

 grows to an inch and a half in length : and 

 has a smooth and glossy skin of a dusky 

 brown colour, but in some seasons greenish, 

 spotted with white. When in motion its 

 back is elevated into a kind of ridge ; and 

 it then appears as if measuring the space it 

 passed over, like a compass, whence its name. 

 Its tail is remarkably broad ; and it holds 

 as firmly by it as by the head. It is common 

 on stones in shallow running waters ; and is 

 often found on trout and other fish after the 

 spawning season. 



Q 3 



