442 



WORMS. 



Leeches are found in marshes and ponds with a bottom of mud or clay, and 

 overgrown with weeds. They cannot live long out of water and die as soon as 



the skin dries, though for some 

 time they may protect them- 

 selves from this by the 

 excretion 

 By day, 



of slimy matter, 

 and especially in 

 warm weather, they swim 

 about with liveliness, but at 

 night and in dark, foggy 

 weather, or on cold days they 

 remain quiet and curled up, 

 and in the autumn they 

 bury themselves deep in the 

 mud. They feed largely 

 upon the blood of fishes, 

 frogs, or mammals, but some- 

 times, in cases of necessity, 

 devour each other. After 

 pairing in the spring, the 

 suctional leeches bore into the 

 soft spongy ground just above 

 the level of the water, and at the end of July or thereabouts begin to form their 

 cocoons or egg-cases, one of which is shown at D in the above illustration. These 

 cocoons are formed of a greenish mucus, or slimy material, and in them from ten 

 to sixteen eggs are laid. The mother then closes the aperture, and over the whole 



COMMON LEECH. 



A, From above (nat. size) ; B, From the side, swimming (nat. size) ; 

 0, Head cut open to show mouth (enlarged) ; D, Egg-cocoon (enlarged. 



STRUCTURE OF LEECH. 



1, Alimentary canal a, (Esophagus ; b, Saccular stomach ; c, Last pair of pouches. 

 2, Anterior end, showing eyes. 3, Jaw. 



pours out a whitish saliva-like froth, which upon drying forms a spongy coating 

 to the case. The cocoons are placed in the burrows, and from four to six weeks 

 after the laying, the young creep forth. These are thread-like and clear, but like 

 the old ones in form ; and appear to attain their full size in about five years, 

 although they may live as many as twenty. 



The colour of the medicinal leech is black above, generally ornamented with 

 pale bands. This species extends over the greater part of Europe, and has been 

 found in France, Germany, England, Russia, and Sweden. Another nearly allied 



