LEECHES. 677 



greenish-black, and by the fact that its jaws are furnished with fewer and 

 blunter teeth. This difference of dentition is evidently correlated with the 

 difference in the feeding habits of the two animals, the food of the Horse- 

 leech, in spite of its name, consisting of such soft-bodied creatures as earth- 

 worms and snails. 



It must not be supposed, however, that all leeches are inhabitants of fresh 

 water. In many countries, indeed, especially in the tropics, land leeches are 

 abundant, as many a traveller knows to his cost. They inhabit jungle and 

 forest land, where the vegetation in the wet season is saturated with moisture; 

 but in the dry season they entirely disappear, presumably burying themselves 

 deep in the earth. According to the accounts of those who have had practical 

 experience of them, these animals are a terrible plague. Gifted with the 

 power of perceiving the presence of prey at some distance, they hasten 

 towards it in crowds from all quarters, or collect in the herbage bordering 

 the forest paths, with head extended, ready to seize hold of any passing man or 

 beast. To protect themselves from their attacks, Europeans are cnmpelled 

 to wear leather or closely-woven cloth gaiters, tied tightly round the knee, 

 while the natives rub their bare legs with oil or lemon juice. 



The leeches of the second family (the Rhynchobdellida;) differ from those 

 belonging to the Gnathobdellidoe, that have been hitherto discussed, in 

 having the front of the body furnished with a protrusible proboscis at the end 

 of which the mouth is situated. To this family belongs the fresh water leech 

 Clepsinc. This animal is yellow, grey, or whitish in colour, occurs on the 

 leaves of plants or on the lower side of stones, and feeds apparently upon 

 water-snails and the young of fresh water mussels. The egas, in number 

 about 200, are not embedded in albumen as is the case in the medicinal 

 leech, but are of larger size and contain their own food-yolk. They are laid 

 in flatfish cocoons which are attached to some stone or water-plant, and the 



leech curls itself round the 

 cocoon to protect it. More- 

 over, when the j'oung are 

 hatched, the mother still con- 

 tinues to look after them, carry- 

 ing them about with her attached 

 to the lower surface of the body. 

 Also belonging to this family 

 is the Warty Sea-leech (Pontch- 

 della mitricata) which is common 

 on our coasts, and may be readily 



Fig, 6.-WARTT SKATE-LEEcn recognlscd by its greenish grey 



(PontoMella muricaia). colour, cylindrical body, and 



tough knobby integument. It 

 is found mostly on fishes of the skate tribe, and hence is sometimes called 

 the, skate-sucker. 



THE GEPHYREAN WORMS. 



Class Gephykea. 



The worms of this class are all marine, and although more or less cylindrical 

 in shape, show scarcely any traces of segmentation. The front of the 

 body is furnished with a large proboscis, and the integument is covered 

 with warts. 



