150 



Arenicolidae 



They are not so markedly different as his figures imply. In each 

 notopodium (Fig. 60) there are from two to four, occasionally five, 

 straight or slightly curved chaetae of the type shown in Fig. 62 b, 

 and a similar number of chaetae, each of which is bent so that the 



Fig. 61. — B. vincentiyas. 

 (" Clymenides incer- 

 tits "). Notopodial 



chaeta. 



Fig. 62. — B. vincenti. Tlie distal portions — 

 in eacli case about tliree-flftlis— of tliiee 

 notopodial chaetae. B, C. Typical adult 

 chaetae ; B is drawn in optical section ; 

 A, transitional form, intermediate between 

 those shown in Fig. 61 and Fig. 62 B. 



distal third or fourth makes with the proximal part an angle of about 

 150° (Fig. 62 c). Both these kinds of chaetae are cylindrical proxi- 

 mally, but beyond the middle of their length they become limbate 

 (cf. Fig. 62 a). The limliate region merges into the tapering terminal 



