DIVISION III. 

 ARTICULATA 



The animals of this comprehensive division, have their 

 bodies, or members, composed of segments or articulated 

 rings, to vi^hich the muscles are attached, on their interior 

 surface. This division contains five classes, namely, Annu- 

 losa, Crustacea, Arachnidce, Myriapoda, and Insecta. It is 

 in the first only that testaceous bodies, like those usually 

 called shells, occur. 



CLASS V.-ANNULOSA. 



Bodies more or less elongated, soft, naked, or enclosed in 

 a tube, consisting of a number of segments, and having red 

 blood. It contains three orders. 



OKDER I -SEDENTAELV. 



Animals protected by a testaceous tube, from which they 

 never issue entirely ; branchiae placed at one extremity of 

 the body, or near it. 



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