162 



NEREIDS. 



ated in front. Segments smooth, lined obliquely on the sides, or not 

 lined, and those of the posterior half dimidiate ; the anal with seta- 

 ceous styles. Feet not decidedly dissimilar to the naked eye, those of 

 the anterior segments smaller and lobulate, very soon receiving their 

 full development, when the organ resembles the annexed figure (No. 

 XXXI.) taken from that of the .36th segment. Dorsal lobe conoid, 



No. XXXI. — Heteronereis lobulata. 



with a globular swelling at its base, in front of which the superior 

 cirrus originates, and reaches to or beyond the point of the lobe ; 

 upper setigerous branch rather small, retreating ; middle lobe conoid 

 like the dorsal, shorter ; under setigerous branch larger than the 

 upper, and with more bristles in its fascicle, overlaid with a veined 

 subreniform entire leaf-like branchia ; inferior to this another conoid 

 lobe, beneath which is the setaceous inferior cirrus with a pair of 

 small papillae at its base, and a small reniform entire branchial leaf. 

 Bristles of superior fascicle {settB spinosce) two-parted, colourless, 

 compound, the shaft cylindrical, cleft at the top, in which is inserted 

 the long needle-like smooth top-piece ; bristles of inferior branch 

 bifasciculate, those of the upper brush of two kinds, one like the 

 bristles already described, and the other {setce falcatce) stouter and 

 shorter, with a cylindrical slightly bent shaft, cut obliquely at the 

 top, where there is articulated a short claw-like piece, smooth, or 



