ON ANNELIDA. 
119 
which may be preserved until it is necessary to employ 
them. 
However abundant 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. Ihe 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- 
corneous 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 w aters, 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. Bose 
