ON ANNELIDA. 119 



which may be preserved until it is necessary to employ 

 them. 



However abmidant these animals may be in our gardens 

 and fields, it seems certain that they do no harm to our gar- 

 dening or agriculture ; and even, as they divide and turn the 

 earth, some persons are of opinion that they are more useful 

 than injurious. 



We have but little knowledge concerning the distribution 

 of the species of this genus on the surface of the earth. 

 They have as yet been studied in a satisfactory manner only 

 in Europe. It is however extremely probable that they 

 exist in North America, and the north of Africa and Asia. 

 >But on this subject we have no positive certainty, and still 

 less so respecting their existence in the southern portions of 

 those mighty continents, or in Australasia. 



The Naides have evidently many relations with certain 

 species of Nereides, and strongly so with the lumbrici. 

 Their intestinal canal is simple, extended from one extre- 

 mity to another of the body, and adherent to the external 

 envelope by cellular bridles. The mouth is round and ter- 

 minal, without any trace of tentacular, or masticatory appa- 

 ratus. The anus is likewise terminal and rounded. We 

 see all along the back of the animal a flexuous vessel, filled 

 with a red fluid, as in the nereides. There is no trace of 

 gills on any of the rings ; but all of them, or almost all, are 

 provided on the right and left with spines, or calcareo- 

 comeous aciculi, simple, and sometimes fasciculate, but 

 always few in number, and pretty nearly as in the lumbrici. 

 The nervous system is almost unknown. These animals live 

 almost constantly in fresh waters, running or stagnant, in 

 the mud or soft clay which border them, and are seldom 

 visible. It appears that they feed on small animals, whether 

 infusory or not, which they probably swallow entire. M. Bosc 



