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reach of the species inhabiting tubes, or which they go in 
search of when they can move, as do the aphrodites, the am- 
phinomse, the nereides, &c. The species which have the 
mouth armed with corneous or calcareous teeth, whether 
trenchant or molar, must use as food living animals, and 
often such as are of a considerable size. Nereides have 
even been found in the holes of teredines, from which it has 
been concluded, that the former preyed upon them. The 
larger nereides with many teeth may doubtless attack pretty 
large animals, even fish perhaps not excepted. 
There are chetopoda, on the other hand, which appear to 
feed only on organic molecules, or at least on the portions of 
organized bodies contained in the soil which they inhabit : 
such are the arenicolm and lumbrici, whose intestinal canal is 
constantly found filled with earth and sand. It is true that 
their mouth is but a simple orifice, without any buccal appa- 
ratus. 
The means which the animals of this class employ to pro- 
cure their food cannot certainly be very inventive ; for those 
which live in tubes, it is sufficient to agitate in all directions 
the barbies with which their heads are adorned, to draw to- 
wards their mouth a current of water, which must bring with 
it a certain number of little animals, or even to seek them and 
draw them towards the mouth by a sort of prehension, executed 
with the assistance of their branchial cirri, or of the barbies, 
when they are provided with them. Certain of those tubico- 
lar species may thus remain in ambush at the entrance of their 
tube, and so much the more easily, as it is often composed of 
grains of sand, or of particles of shells, in all respects similar 
to those which constitute the surrounding soil. 
The free and vagrant species may go in search of the 
objects which suit them, but in all probability they lay no 
ambush. 
The lumbrici, thalassemse, and the arenicolse, have only to 
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