78G 



ON THfi CHJi:T080MATID^, 



sist each of 14-17 compound sette (Figs.26, 27, i.?-., i.r'). The 

 composition of the outer rows differs in the two sexes. In the 

 female (Fig.27, or.), there are 10-14 compound setse in each row; 

 in the male, 7-11 compound seta?, and 4-5 simple seta? alternating 

 irregularly (Fig. 26, .s-.^-., C.6-.). In young worms, the number is 



Fig. 26. —Ch . JiHsirell'i. " Fig. 27. —Ch , hasirelli. \ 



much less. In one specimen, wliich has only a single row of four 

 head-seta^, theie are five set.e in each outer row. Another young 

 worm, 0*60 mm. long, which appeared to belong to this species, 



* Posterior end of male, showing the arrangement of trunk-hairs and 

 ventral setse; (x 400). The penial seta? are visible through the body-wall 

 {p.s.); a,.s,, sette surrounding the anus; pr.s., pre-anal set*, 



t Po.sterior end of female, showing the arrangement of hairs and seta? 

 on the surface, and also some of the internal structure, as seen through the 

 body-wall; ( x 400), Fig.27a. — Seta of inner row of ventral set;e; ( x 030). 

 Fig.27/'. — Seta of outer row; ( x 630). 



