CLASS ANNELIDA. 
i 
Division of the Annelida into Three Orders . 
This not very numerous class, presents in its respiratory 
organs, the bases of satisfactory divisions. 
Some have gills in the form of plumes, or arbusculm, at- 
tached to the head, or to the anterior part of the body. Almost 
all of them inhabit tubes. These we call TuBiCGLiE. 
Others have on the middle part of the body, or along the 
sides, gills in the form of trees, tufts, laminae, or tubercles, in 
which the vessels ramify. Most of them live in the mud or 
ooze, or swim in the sea. The smaller number have tubes. 
We name them Dorsibranchia. 
Others, in fine, have no apparent gills, and respire, either 
by the surface of the skin, or as some believe, through internal 
cavities. Most of them live freely in water or mud ; some 
only in humid earth. We call them Abranchia. 
The genera of the first two orders have all stiff hairs, or 
bristles, and of a metallic colour, issuing from their sides, 
sometimes simple, sometimes in bundles, and supplying the 
place of feet. But in the third order there are some genera 
destitute of such support *. 
The special study which M. Savigny has devoted to those 
feet, or organs of locomotion, has caused him to distinguish, 
1. The foot itself, or the tubercle which supports the bristles: 
sometimes there is but one to each ring ; sometimes there are 
two, one above the other ; this is what is named simple or 
double oar. 2. The bristles which compose a bundle for 
* M. Savigny has proposed a division of Annelida, according to their 
having bristles for locomotion or not; these last being reduced to the 
leeches. M. de Blainville, who has adopted this idea, makes of the An- 
nelida which have bristles his class of Entomozoa chetopoda , and of those 
which have none, that of Entomozoa apodaj but (what M. Savigny did 
not do) he intermingles, among the apoda, several of the intestinal worms. 
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