ORDER ANNULATA APODA. 109 



exist on the blood or other juices of the creatures on 

 whose body it fixes itself; this is not the case with the 

 horse-leech, which lives entirely on the larvoB of aquatic 

 insects, worms, &c., so that the common idea of the 

 danger of the bite of the horse-leech is without foundation. 



The horse-leech is exceedingly voracious, not only 

 swallowing worms, tadpoles, &c.,but even preying upon 

 its own species. Sixty-five horse-leeches were placed 

 in a glass vessel, and in five days the number was 

 reduced to fifty-two, and not a vcbtige of those that were 

 missing was to be discovered. 



The usual slowness of action of the digestive powers 

 in all animals of cold blood, was curiously illustrated in 

 the case of a horse-leech, which, after swallowing two 

 small leeches of a different species, disgorged one of the 

 two at the end of three days, in a living state, and appa- 

 rently not much injured from its sojourn in so unusual 

 a lodging ; but it enjoyed its liberty only for a few hours, 

 its more powerful companion swallowing it a second time 

 at the end of that period. 



A number of this species of leech, inhabiting the 

 water that supplied a trough in which a tench had been 

 placed, fixed themselves to different parts of the body 

 of the fish, and so effectually was the poor tench annoyed, 

 that it w'as soon deprived of life. " The leeches then tore 

 it (previously breaking the line of connexion between 

 the various parts of the body, by inflicting a vast num- 

 ber of bites or wounds,) into such pieces as they could 

 readily receive into the stomach, and so diligent were 

 they, that in a few days nothing remained of the fish but 



the mere skeleton." 



« 



From these habits it would appear, that the name of 

 Hirudo sanguisuga, (the blood- sucking leech,) has been 



