140 



ZOOLOGY 



correspond with one metamere, but there are three, four, 

 or five segments to a metamere. Leeches have no para- 

 podia and no bristles; but they have a sucking disk at 

 the posterior end of the body for the purpose of adhesion 

 (Fig. 127). They usually have a smaller, anterior sucking 

 disk around the mouth, which may or may not be provided 

 with teeth, for the purpose of cutting through the skin. 

 When there are no teeth, the pharynx is protrusible, 

 forming a proboscis. With a few exceptions, all leeches 



FIG. 127. Clepsine, the flat blood-sucker. Ventral view. Posterior sucker at 

 left. Nat. size. From life. Photo, by E. R. D. 



live in water ; but in Ceylon there is a land leech which 

 lives in foliage and attacks man and other animals. Other 

 leeches may live in damp places at a considerable distance 

 from water. Leeches suck the blood of fishes and other 

 aquatic animals. Certain kinds devour worms, insects, and 

 other small creatures. 



The commonest of the larger blood-suckers of our waters 

 is Nephelis, 1 which is not distinctly segmented. It varies 

 from black to slate color, arid is sometimes striped or 

 spotted. It lives in running water, in ditches, and ponds. 



, wife of Athamas. 



