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HIRUDINEA 



HIRUDINEA. 



THE MEDICINAL LEECH. 



i. Hirudo medicinalis. A dorsal, and B ventral aspect, of a medicinal leech killed by chloroform 

 vapour. Annuli (95 in number), superficial constrictions, of which, in most regions, five appear to 

 make up one segment or metamere as indicated by the deep-lying organs ; oral sucker and mouth ; 

 posterior sucker; anus dorsad of the sucker; penis between 24th and 25th annulus, counting from 

 the edge of the mouth; eyes (5 pairs). 



