LEECHES. 



44: 



species, H. officinalis, which is of an olive-green, unspotted colour, is most abundant 

 in the south and south - east of Europe. Other kinds are found in Morocco, 

 Senegal, India, and North America. In some parts of the tropics, such as India and 

 Ceylon, land-leeches, which abound in meadows and woods, are a terrible plague. 

 They live on grass or trees, are exceedingly quick in their movements, scent prey 

 from a long distance, and troop in numbers to the spot. Hence a person brushing 

 through the jungle becomes covered with them, unless some precautions are taken. 

 Another well-known member of the group is the horse-leech (Aidostoma 

 gido), characterised by its blackish green colour, the great narrowing of the fore- 



ROCK-LEECH (uat. size) 



part of the body, and the presence of only three small teeth in the mouth. Many 

 stories are current as to the dangerous nature of these leeches, and it is even said 

 that nine of them will suck a horse to death ; but although doubtless a voracious 

 creature, it is certain that such accounts are fallacious. The horse-leech lives on 

 earth-worms, snails, grubs, and other leeches, and even creeps into the shells of 

 fresh-water mussels, and takes up a lodging there until it lias devoured the inmate. 

 Another form that abounds in fresh-water ponds and streams is Nephelis vulgaris, 

 which reaches a length of nearly two inches, and has Pour pairs of eyes and tooth- 

 less jaws. It appears to feed partly on animal and partly on vegetable food. 

 A second group of the leeches are the Clepsinidce, recognised by the short flat 

 body, which towards the front is usually stumpy, and ends in a seizing disc 

 carrying the eyes. The gullet, which is toothless, can be protruded like a proboscis. 



