NATURAL ARRANGEMENT OF INSECTS. 



these relations indeed exist, and yet may be accounted 

 for upon the simple principle, that the Nereida, in their 

 own circle,, represent the Myriapoda, hut without having 

 any affinity to them. As we have had no opportunity 

 of studying these animals, we shall depart somewhat 

 from our usual practice., and, instead of venturing upon 

 any arrangement of our own, shall here lay before the 

 reader the views entertained of their natural classifi- 

 cation by others. 



(l6.) Cuvier, who first discriminated this class by 

 the name of Fers a sang rouge, has arranged them into 

 three orders, founded upon their different modes of 

 respiration. These are named Tubicoles, Dorsibranches, 

 and Abranches. The first have their branchiae in the 

 form of a plume of feathers, attached to the head or 

 to the anterior part of the body ; which latter is always 

 protected by a tubular sheath. The second have the 

 branchiae disposed on the sides of the body, where they 

 assume the form of little ramified branches, tufts, plates, 

 or tubercles : the greatest number live in the mud or 

 freely swim in the ocean ; but some few inhabit tubes, 

 like the former division. The third class comprehends 

 such as have no apparent branchiae, and which respire 

 from the surface of the skin, or, as it is supposed, by 

 interior cavities. The greatest part of these animals 

 live at the bottom of the sea, but a few reside in humid 

 ground, like the earth-worm. The learned Savigny 

 divides the Annelides into five orders, three of which 

 are furnished with those bristly appendages on the 

 sides of the body which perform the office of feet, and 

 which are wanting in the other two.* Lamarck's ar- 

 rangement of the Annelides is founded upon the facts 

 disclosed by Savigny. He divides the whole group 

 under the three following orders : 1 . Annelides apodes, 

 or footless Annelides ; 2. Annelides antennees, or such 



* Mentioned in Horce Entomologies, p. 281. The recent arrangement 

 of MacLeay, hereafter noticed, seems to be precisely the same as Savigny 's, 

 - at least, in the primary divisions. 



