CHAETOPTERTDAE. 365 



and in P. anglica Potts bundles of parallel divisions (Potts, Op. cit., p. 984). 

 A current of water is kept constantly flowing through the tube, primarily by 

 means of the cilia lining the dorsal groove. From this respiratory current 

 food-materials are secured. The securing of food is aided by the usually long 

 tentacles which ordinarily are protruded from the mouth of the tube and are 

 moved over the surrounding surface, sweeping up diatoms and other small 

 organisms which are carried by the current formed by their ciliated grooves to 

 the mouth of the tube into which they are drawn. ^ 



These annelids occur between tide-marks and at moderate depths, though 

 sometimes found in comparatively deep water. 



Other animals sometimes occur in the tubes of the chaetopterids as com- 

 mensals. Thus in tubes of C. pergamentaceus {C. variopedatus) have been found 

 Polynoe setossisima Savigny, Gattyana cirrhosa (Pallas), and the polyzoan 

 Hypophorella chaetopteri (Joyeux-Laffuie) (Cf. Archiv. zool., 1890, ser. 2, 8, 

 p. 335). 



Key to Genera. 



a. Body divided into three regions. 

 b. Peristomium with a single pair of appendages (tentacles). 

 c. Median region consisting of five somites of which the first bears separate fin-like notopodia 

 and the others notopodia united across the dorsum to form conspicuous single fans or suckers. 



Chaetopterus Cuvier. 

 cc. Median region consisting of two or three somites in which all the notopodia remain separate. 



d. Notopodia of median region bilobed and foliaceous Spiochaetopterus Sars. 



dd. Notopodia of median region unilobed and conical Mesochaetopterus Potts. 



bb. Peristomium with a second pair of smaller tentaculiform appendages in addition to the ordinary 

 tentacles. (Notopodia of middle region foliaceous and bilobed or multilobed). 



Phyllochaelopterus Grube. 

 aa. Body divided into but two regions. 



b. Notopodia of the posterior region all undivided Rarizanides, nom. nov.^ 



bb. Notopodia of the posterior region all two-lobed Telepsavus Costa. 



Synonymy of Genera. 



The genus Tricoeha of Renier was estabUshed in 1848 with T. variopedatus 

 as the type. But this species is identical with pergamentaceus, the tjrpe of Cuvier's 

 Chaetopterus (1830) . Some authors, however, have given precedence to Renier's 

 species, apparently under the assumption that Renier's Prospetto dei Vermi 

 (1804) was pubhshed and distributed. If the species variopedatus is given 

 precedence over pergamentaceus, then Tricoeha is vahd and must be used instead 



1 For the more complicated feeding methods see Enders, Life history and habits of Chaeloptems 

 variopedattts, Journ. morph., 1909, 20, p. 479-431. 



'Pro Ranzania Claparedc (1875), nee Bonaparte (1841), nee Bcrtoloni (1855). 



