176 



Aquatic Organisms 



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I 



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leeches will make a feast of vertebrate blood, if occasion 

 offers, or in absence of this will swallow a few worms 

 instead. 



The mouth of leeches is 

 adapted for sucking, in some 

 cases it is armed for making 

 punctures, as well: hence the 

 food is either more or less fluid 

 substances like blood or the 

 decomposing bodies of dead 

 animals, or else it consists of 

 the soft bodies of animals 

 small enough to be swallowed 

 whole. 



The eggs of leeches are 

 cared for in various ways: 

 commonly one finds certain 

 of them in minute packets, 

 attached to stones. Others 

 {Hcemopis, etc.) are stored in 



XI larger capsules and hidden 

 I amid submerged trash. Oth- 

 ers are sheltered beneath the 

 body of the parent, and the 

 young are brooded there for 

 a time after hatching, as 

 shown in the accompanying 

 figure. Nachtrieb (12) states 

 that they are so carried ''until 

 the young are able to move 

 about actively and find a host 

 for a meal of blood." 

 Leeches are doubtless fed upon by many carnivorous 

 animals. They are commonly reported to be taken 

 freely by the trout in Adirondack waters. In Bald Moun- 

 tain Pond they swim abundantly in the open water. 



V*- 



Fig. 84. A clepsine leech 

 {Placobdella rugosa), over- 

 turned and showing the 

 brood of young protected 

 beneath the body. (From 

 the senior author's General 

 Biology). 



