ANNELIDA. 



The Earth-worm, the Leech, and similar animals come under 

 this class. They derive their name from the numerous ring-like 

 joints of which their bodies are composed. They dwell in water 

 or in clay or wet sand, and many of them live on the juices which 

 they suck from other animals. Excepting the leeches, they all have 

 little appendages oh each side of every ring of the body, furnished 

 with silky hairs and bristles, for the purposes of respiration and 

 locomotion ; and by these it is easy to decide upon the class to 

 which they belong. Many of those which Kve in the sand, or 

 under stones and in mud along the shore, are used as bait for 

 fishing. 



Leeches. There are three large species of Hirudo, besides 

 numerous smaller ones. But they have not been studied, and do 

 not seem even to have received a name, unless from Bosc, whose 

 work I have not seen. There is the common Blood-sucker, 

 which is not unfrequently employed in the country for medical 

 purposes. Its value has not been properly tested ; but while for- 

 eign leeches, which are always safe and sure in their operations, 

 can be so readily obtained, it is not probable that our leech will 

 be extensively employed in large cities. 



The Horse-leech is very large and long, distinguished by its 

 bluish-black back and its ochre-colored belly, which may be com- 

 pared to the inner surface of calf-skin leather. Its bite is not 

 disposed to heal readily. 



The ToRTOisE-LEECH, (^Hirudo parasitica, Say, Append, to 

 Long''s 2d Exped. ii. 266,) is a third. It is flattened, somewhat 

 oval in form, granulated and wood-colored upon the back, with 

 each margin checked by a line of dark, square spots. It may 

 often be found adhering to bits of wood in ponds, with a brood of 



