ANNULATA. 237 



Annttides dorsibranches of CUVIER, whilst, however, in a natural arrange- 

 ment it might better remain with the Amphitritce, Ann. des Sc. nat. sec. 

 Se'r. x. Zool. p. 208. 



** Naked, roving. 

 (Commonly NotobrancMate, Dorsibranches ClJV.) 



Family VII. Arenicolce ( Telethusce SAV.) Rudiments of feet 

 of a dorsal fasciculus of setae and a ventral transverse tubercle with 

 setae very minute, plane, incurved. Branchiae arborescent in the 

 middle of the body, with a double row at the sides of fasciculi of 

 dorsal setae. Head not distinct; eyes and jaws none. 



Arenicola LAM. Body elongate, with segments subdivided by 

 transverse folds, incrassated forwards, becoming smaller backwards, 

 without setas or other appendages behind the last pair of branchiae. 

 Mouth terminal supplied with a proboscis retractile, papillose. 



Sp. Arenicola piscatorum, Lumbricus marinus L., Nereis himbricoides, PALLAS 

 Nov. Act. Petrop. n. 1788, p. 223, Tab. v. f. 19, 19*; HOME Phil. 

 Transact. 1817, Pt. i. Tab. 3 ; OKEN, his, 1817, p. 469, with fig. ; AUDOUIN 

 and MILNE EDWARDS, Ann. des Sc. nat. Tom. 30, 1833, PI. 22, fig. 8. 

 This species has thirteen pairs of gills. It lives in deep canals excavated in 

 the sea-sand, which the worm forms with its head, whilst the sand is 

 swallowed and passed through the intestinal canal ; this worm is flesh- 

 coloured, sometimes blackish (Arenicola carbonaria LEACH), and exudes a 

 yellow fluid on being touched. Fishermen use it as bait to catch shell-fish 

 with the hook. Arenicola branchialis AUD. and EDW. 1. 1. fig. 13, has nine- 

 teen or twenty pairs of gills, and is smaller than the former. Arenicola 

 Bcechii RATHKE, Fauna Norwegens, p. 181, Tab. viu. f. 19 22, differs from 

 the former species by the much more numerous gills and by the rings, 

 which lie behind the last pair of gills, possessing bundles of hairs ; also the 

 anterior part of the body is not incrassated like the former species. It 

 seems, therefore, that this species should form a sub-genus. 



It seems that the genus Scalibregma RATHKE ought to be added 

 to the Arenicolse : it has four pairs of arborescent branchiae (in the 

 fourth, fifth, sixth and seventh segment) with a proboscis not warty ; 

 1. 1. p. 182, Tab. ix. figs. 1521. 



Family VIII. Chcetopterina. Anterior and posterior rudiments 

 of feet with a fasciculus of dorsal setae, without uncinate setae, the 

 middle feet with a dorsal appendage, membraneous, large (bran- 

 chial?). Head not distinct; maxillae none. 



Chcetopterus Guv. (Worm elongate, included in a coriaceous 

 tube). 



