's RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 



63 



TV = 8 paragnaths, situated upon a crescent, triangular plate ; the 3 

 largest ones at the internal side. 



Ill = 3 paragnaths, one behind the other. 



The paragnaths of each group appear to be situated upon a common 

 plate. The maxillae are provided with 4 to 5 stout denticulations. 



In the parapodia of the anterior body-region the superior ligula is 

 short, rounded, somewhat projecting beyond the anterior dorsal lip, which 

 is as long as the median ligule; the ventral lobe with its anterior lip 

 somewhat extending beyond the inferior ligule. Both have a rounded, 

 distal extremity. The dorsal cirrus a little longer than the superior ligule, 

 whereas the ventral one is some- 

 what shorter than the inferior ligule. 

 In the anterior 7 parapodia the ba- 

 sal part of the dorsal cirrus is en- 

 larged ; the anterior 6 parapodia 

 have the ventral cirrus enlarged 

 in its basal part. The dorsal bristle- 

 fascicle consists of homogomph 

 setigerous setae ; the ventral fas- 

 cicle in its superior part contains 

 some . homogomph setose bristles 

 and some stout, yellow, hetero- 

 gomph falcate ones, with anchylo- 

 sed articulation and provided with 

 a short terminal piece that has an 

 enlarged apex and a ligament bent 

 down over its edge. The inferior 

 part of this fascicle consists of heterogomph setose bristles and some 

 heterogomph falcate ones, which are provided with a terminal piece, that 

 is more slender than that of the falcate setae in the superior part. The 

 aciculae are dark black. The epitocous transformation of the parapodia 

 commences in the 14 lh or 15 th parapodium (in the specimen from Noi- 

 mini in the XYI th ); in the 14 th - one already a small, round lamella is 

 visible at the base of the dorsal cirrus, whereas small appendages are 

 developed at the dorsal and ventral side of the base of the ventral cir- 

 rus. The swimming bristles at the first time appear in the 15 ,h parapo- 

 dium. In the parapodia of the epitocous body-region the superior ligule 

 has grown long and slender of an elongated oval shape, whereas the 

 dorsal cirrus with its thin, distal end extends beyond the extremity of 

 the ligule ; at the ventral side of the dorsal lobe as well as at the supe- 

 rior border of the ventral lamella ramous appendages are visible. 



