450 PROCEEDINGS OF THE ACADEMY OF [XoV., 



bases of the setae, which are arranged in a broad vertical fan (fig. 2, a). 

 The first seven pairs of parapodia have no notopodia whatever, the 

 succeeding ones on sexually mature worms bear notopodial setigerous 

 sacs on the dorsal face of the base of the neuropodium, but there is no 

 distinct notopodial elevation or lobe. 



On the first three metastomial segments the notocirri are exactly 

 like the peristomial cirri in both form and size. Succeeding ones 

 become more slender and tapered, with the tip often abruptly more 

 slender, and increase in length until they ecjual the width of the seg- 

 ments. They also become distinctly jointed or even beaded (fig. 2, a). 

 In the middle of the body they are as long as the body diameter and 

 have 7-8 divisions. There is a great difference in this respect in 

 different specimens, some having the cirri much more strongly monili- 

 form than others. Sometimes there is a slight but distinct alterna- 

 tion of longer and shorter cirri, the former being always the more 

 strongly beaded; but these conditions are not constant. Posteriorly 

 the cirri become again shorter. Neurocirri (fig. 2, a) are coalesced with 

 the ventral border of the neuropodia to near the end, where the styles 

 become free and reach to the ends of the ventral setae. They are 

 sub-conical, usually with irregular constrictions and thickenings and 

 a more slender blunt terminal piece. 



Aciculum single, neuropodial only, rather stout, tapered, straight or 

 slightly curved, extending obliquely nearly into the dorso-lateral 

 angle of the neuropodium, beyond w^hich it projects and terminates in 

 a large, flattened and roughened knob (fig. 2, b). Neuropodial sette 

 of two kinds, both longer, than the parapodium and colorless. The 

 first (fig. 2, d) is a single and never more, moderately slender, simple 

 seta arising dorsal to the end of the aciculum of each parapodium, 

 curved and slightly thickened distally, finely toothed along the convex 

 side and slightly enlarged and bifid at the end. The second form is 

 compound (fig. 2, c). These form spreading vertical subacicular tufts 

 which on the more anterior parapodia contain 20 or more in several 

 ranks, the number becoming gradually reduced to 10 or 12 on middle 

 segments and 7 or 8 posteriorly. Shafts more slender than the simple 

 setffi, slightly curved, deeply unequally bifid distally, with a single 

 small accessory tooth on the side of the larger division. Appendages 

 delicate, slender, elongated, the longest anterior dorsal ones equalling 

 the diameter of the parapodium, but diminishing toward the ventral 

 side posteriorly until they are only ^ as long. Distally they are divided 

 into two slender, unequal, slightly curved teeth separated by a narrow 

 cleft. Apparently the margins are finely fringed, but this appearance 

 disappears posteriorly. 



