286 ARTICULATA. 



POLYNOE, Savigny. 



Where there is none of this tow on the back they have five tentacula, and 

 their proboscis is furnished with strong and horny jaws. 



This is the only situation we can assign to a new and very singular 

 genus, which I call 



CH.KTOPTEROS, Cuvier. 



The mouth has neither jaws nor proboscis, and is furnished above with a lip, 

 to which are attached two tentacula. Next comes a disk with nine pairs of 

 feet, followed by a pair of long silky fasciculi resembling wings. The lamel- 

 lated branchiae are rather beneath the body than above it, and extend along 

 its middle. 



Chastopterus pergamentaceus, Cuv. This species, which is found at the 

 Antilles, is from eight to ten inches in length, and inhabits a tube resembling 

 parchment. 



ORDER III. 

 ABRANCHIATA. 



THE Abranchiata have no apparent external organ of respiration whatever, 

 and appear to respire, some, like the Lumbrici, by the entire surface of the 

 skin, and others, like the Hirudines, by internal cavities. They have a closed 

 circulating system, usually filled with red blood, and like all the Annulata, a 

 knotted nervous cord. Some are also provided with setae which enable 

 them to crawl, .and others are deprived of them. This has caused their 

 division into two families. 



FAMILY I. 

 ABRANCHIATA SETIGERA. 



THIS first family comprises the Lumbrici and Naides of Linnaeus. 

 LDMBRICUS, Linnaeus. 



The Earth-wormt, as they are commonly called, characterised by a long, 

 cylindrical body, divided by rugae into a great number of rings, and by an 

 edentated mouth, necessarily required to be subdivided. 



LUMBRICUS, Cuvier. 



Eyes, tentacula, branchiae and cirri, all wanting. The nervous cord is 

 nothing more than a crowded suite of numerous little ganglia. 



