140 ANNELIDES. 



A large species is fovmd at tlie Antilles which inhabits a tube 

 of the consistence of leather *, 



Tliis is the only situation we can assign to a new and very singu- 

 lar genus whicli I call 



CHiETOPTERUS, CuV. 



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

 Avith a lip, to whicli are attached two tcntacula. Next comes a disk 

 with nine pairs of feet, followed by a pair of long silky fasciculi re- 

 sembling wings. The lamellatcd branchioe arc rather beneath the 

 body than above it, and extends along its middle. 



ChcEtopteriis pergamentaceus, Cuv. This species, which is 

 found at the Antilles, is from eight to ten inclx>s in length, and 

 inhabits a tube resembling parchment f . 



ORDER III. 



ABRANCHIATiE. 



The Abranchiate have no apparent external organ of respiration 

 whatever, and appear to respire, some, like the Lumbrici, by the en- 

 tire 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 Annelides, 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. 



* N.B. The PhijUodoce mnxillosa of Ranzani, called Polyodonte by Reinieri, 

 find Eumolpe maxima by Oken, seems to be closely allied to the Acoetes ; its pro- 

 boscis and jaws are the same, and neither of the genera has, perhaps, been described 

 from perfect specimens. 



There remain various Annelides so imperfectly described, that we are unable to 

 characterize, them well; such are thfe Nereis caca, Fabr., Soc. Hist. Nat. Copen. 

 parti, pi. iv, f. 24 — 23; — iV, longa, Id., lb., f. 11 — 13; — A^ aphroditoMes, lb., 

 4 — 7; lb., 11 — 13; — Branchiarfi'.s quadranguJatus, Montag. Lin. Trans., XII, pi. 

 xiv, f. 5 ; — Diphtes hyalina, Id., lb., f. 6 and 7 ; and the pretended Hirudo hi-an- 

 chiata, Archib. Menzies, Lin. Trans. I, pi. xvii, f. 3. I have also omitted the 

 Myrian.is and two or three other genera of M. Savigny, on account of my having 

 Jiad no opportunity to re-examine them. 



f It will be more minutely described by Messrs. Aud., and Cuv., in the Annales 

 des Sciences Naturelles. 



I For the anatomy and physiology of the abranchiate Annelides, see the Memoir 

 of M. Ant. Di'.fjh, Annales des Sciences Naturelles, Sept. 1828. 



