PARASITES FREE DURING THEIR WHOLE LIFE. Ill 



side of the stomach are seen traces of the glands of 

 the skin. 



We find a great variety in the mode of hfe of these 

 hirudinid£e ; and if we sometimes meet with some which 

 are soher and deHcate, the greater part show a voracity 

 of which it is difficult to form any idea. A leech has 

 heen met with in Senegal which draws a quantity of 

 hlood equal to the weight of its body. There are leeches 

 which devour entire earth-worms. Fortunately the 

 greater species are not the most voracious : we might 

 feel rather uneasy in the midst of leeches similar to that 

 w^hich Blainville has described under the name of Ponto- 

 hdella Isevis, which is not less than a foot and a half in 

 length. 



It is generally thought that all leeches are aquatic, 

 but this is a mistake. In the warm regions of the Old 

 and New World, there live in the midst of the brush- 

 wood, leeches w^hich attack the traveller as w^ell as 

 his horse, and suck the blood of both without their 

 perceiving it. 



Hoffmeister gives the following account with reference 

 to small leeches in the island of Ceylon : — 



He had amused himself one evening by collecting 

 some phosphorescent insects which were hovering around 

 him in considerable numbers ; on entering afterwards a 

 lighted room, he perceived streaks of blood all do\\Ti his 

 legs. This was the effect of the bites of leeches. These 

 creatures, said he, made a painful impression on me, the 

 remembrance of which was terrible. This same leech, 

 which bears the name of Hirudo tagalla, or Ceylonica, 

 lives in the thickets and woods of the Philippine Islands. 

 There also it attacks horses as well as men. It has 



