368 



ANNELIDA. 



The form of the movable sette varies extremely, and affords a good 

 character for the classification of families and genera. According 

 to the strength, form, and mode of ending (fig. 298), the following 



a, ic a e. / 5 



FIG 298. Setfe of different Polycliietit (after Malmgren and Claparede). a, Hooked seta of 

 Sabdtii ei-uxxicoraig ; l>, of Te rebel I a Dmiielggeni ; c, seta with piral ridge from tStkenelais ; 

 d, lance-shaped seta of Phylloehcetoptemu ; e, of Sabella erassicornis ; f, at Sabella pavonis ; 

 ff, Composite sickle-shaped seta of Nerds cultrifera. 



forms can be distinguished : hair-setae, hooked-seta?, fiat-setae (pcdece), 

 lance-seta?, sickle-shaped seta?, etc* When the parapoclia and their 



appendages are com- 

 pletely wanting, the 

 seta? are embedded in 

 pits in the integument, 

 and are arranged either 

 in one or two rows on 

 either side, that is, in a 

 lateral ventral row on 

 either side, or in a ven- 

 tral row and a dorsal 

 row on either side. In 

 such cases the number 

 of seta? is small (Oligo- 

 chceta}. The seta? may, 

 on the contrary, be pre- 

 sent in great number, 

 so that the integument 

 on either side seems to 

 be covered with long hairs and seta?, and a thick felt of hairs 

 shining with a metallic lustre is distributed over the whole dorsal 



FIG. 299. Anterior end of Pnlynoii fxteiinufa, the first 

 elytron on the left hand being removed (after Cla- 

 parede). The two setae of the oral segment are visible ; 

 El, Elytra. . 



