ANNELIDES. 127 



tubes there with the ooze or other matters, or even exude a calcareous 

 substance, which envelopes them with a sort of tubular shell. 



Division of the Annelides into three Orders. 



This class, which contains but few species, presents a sufficient 

 basis of division in its organs of respiration. 



The branchiae of some resemble tufts or arbusculae, attached to the 

 head or anterior part of the body : they, nearly all, inhabits tubes. 

 We will call them the Turicol^. 



Those of others resemble trees, tufts, laminae or tubercles in 

 which vessels ramify, and are placed on the middle of the body : 

 most of them inhabit mud or swim in the ocean, the smaller portion 

 being furnished with tubes. We name them the Dorsibranchiat^. 



Others again have no apparent branchiae, and respire, either by 

 the surface of the skin, or as some authors opine, by the internal 

 cavities. Most of them live free in mud or water ; some of them 

 only, in humid earth. They are the Abranchiat/e. 



The genera of the first two orders are all furnished with stiff setae, 

 of a metallic colour, that issue from their sides, sometimes simply, 

 and at others in fasciculi, which serve in lieu of feet; but there are 

 some genera in the third order which are deprived of that support*. 



The special attention paid by M. Savigny to these feet or organs 

 of locomotion, has resulted in the distinction of the following parts : 

 1. The foot itself, or the tubercle which supports the setse; some- 

 times there is but one to each ring, and at others there are two, one 

 above the other, styled a simple or double oar. 2. The setae, which 

 compose a fasiculus for each oar, and which vary greatly in form and 

 consistence, sometimes constituting true spines, and at others, fine and 

 flexible hairs, frequently dentated, barbed, &c.t 3. The cirri or 

 fleshy filaments adhering to the foot, either above or beneath. 



The head of the Annelides of the two first orders is generally fur- 

 nished with tentacula or filaments, to which, notwithstanding their 

 fleshy nature, some modern naturalists give the name of Antennae ; 

 and several genera of the second and third, are marked with black and 

 shining points, usually considered as eyes. The organization of their 

 mouth varies greatly. 



* M. Savigny has proposed a division of the Annelides, to be founded on the 

 presence or absence of these locomotory setae ; those in -which they are -wanting 

 being reduced to Leeches. M. de Blainville, -who has adopted this idea, forms his 

 class of the Entomozoari.e Chetopodes with the Annelides that have seta, and 

 that of the Entomozoarke Apodis -with those which have none, but in mixing 

 many of the Intestini -with the Apodes, he has done what M. S. did not do. 



f See on this subject, the Mem. of M. Savigny on the invertebrate animals, and 

 those of Messrs. Audouin and M. Edwards on the Annelides. 



