04 



ZOOLOGISCHE MEDEDËELINGEN — DEEL IV. 



lips, the anterior of which somewhat extends beyond the posterior one; 

 the ventral ligule is shorter than the neuropodial lobe, whereas the 

 ventral cirrus does not reach the extremity of the ligule. In the median 



body-region the dorsal lobe and the dorsal 

 ligule acquire a more conical shape and are 

 nearly of the same length, whereas in the 

 posterior segments the dorsal ligule grows 

 more slender and extends beyond the noto- 

 podial lobe; also the ventral ligule increases 

 in length and reaches beyond the distal end 

 of the neuropodial lobe. The aciculae are 

 dark blackish. The notopodial fascicle in the 

 anterior segments contains only homogomph 

 setose bristles ; in the median body-region 



wC^yr however in the ventral part of this fascicle 



some homogomph falcate bristles appear. The 

 terminal joint of these bristles does not possess 

 cilia and their tip is capped. The neuropodial fascicle consists dor sally 

 of homogomph setose bristles, with some heterogomph falcate ones, whereas 

 its ventral part contains heterogomph falcate bristles and some heterogomph 

 setose ones in the posterior segments. 



The epitocous transformation of the parapodia (Heteronereis) in the 

 male commences at the 16th segment. A fully developed parapodium of 

 this region (Fig. 2) has the superior ligule, near the base of the dorsal 



cirrus, provided with a small, 

 oval lamella, whereas the in- 

 ferior ligule bears a blunt, coni- 

 cal process on its dorsal border. 

 A large rounded lamella, with 

 an oval appendix at the dorsal 

 part of its posterior margin, is 

 developed around the tip of the 

 neuropodial lobe and an other 

 narrow, oblong lamella occurs 

 at the base of the ventral cir- 

 rus. This cirrus is strongly 

 elongated, reaching beyond the 

 extremity of the ventral ligule ; 

 the dorsal cirrus also is rather long and shows 10 or 11 papillae along 

 its ventral side. Both lobes of the parapodia have setose bristles with 

 knife-shaped terminal pieces of ordinary appearance. The head of the 



Fig. 2. 



