502 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 10 



what coiled and twisted in its posterior portion, especially where the 

 dorsal acicular spines are most developed. Parapodia come to be rela- 

 tively more conspicuous in the posterior half of the body due mainly to 

 the great dorsal projecting hooks and the long dorsal cirri. 



The prostomium is more conspicuous than usual for members of this 

 family. There are paired lateral lobes and a median one but they are 

 separable in external view with difficulty. Each gives rise to a long 

 tentacular antenna (pi. 61, fig. 1). There are no eyes. The posterior 

 margin of the prostomium is nearly straight or only slightly convex. The 

 palpi are prolonged and directed forward in front of the prostomium. 

 They consist of thick palpophores and small palpostyles. The palpi are 

 well separated from each other medially by the middle lobe of the pros- 

 tomium. 



The peristomium or first segment is separated from the prostomium 

 by a shallow groove. It is nearly twice as long as the first seti'gerous seg- 

 ment and distinctly biannulate. At its anterior, lateral margins there 

 are 2 pairs of long, tentacular cirri arising from short, simple bases. The 

 ventral pair is somewhat smaller and shorter than the dorsal pair and all 

 resemble the prostomial antennae in form. 



The proboscis, partly everted in one individual, is smooth, cylindrical 

 and muscular. It terminates distally in a circlet of 14 large, conical 

 papillae (pi. 61, fig. 2). Its proximal surface is smooth and somewhat 

 iridescent except for wrinkles of contraction. By transmitted light one 

 can distinguish heavy, striated muscles in the walls of the proboscis. 

 There are no jaws or other chitinous pieces. 



The first setigerous segment is conspicuous for a pair of long, tentacu- 

 lar cirri that are longer and thicker than the median prostomial antenna. 

 The ventral cirri are much smaller, resembling those farther back. The 

 setigerous lobe is provided with a whorl of fine, pointed setae. The 

 second setigerous segment resembles those farther back but it is some- 

 what reduced on its ventral side so that ventral cirri are lacking (pi. 61, 

 fig. 3). Its notopodium is represented by a long, cirriform, dorsal cirrus 

 and a yellow,translucent aciculum that extends into the cirrus. Its 

 neuropodium is well developed with an acicular lobe and a full fascicle of 

 long, slender, pointed setae. From the next segment there is little dif- 

 ference in successive parapodia except for proportionate differences in size, 

 depending on position. Anterior and median parapodia are lateral in 

 position ; posterior ones are dorsolateral so that dorsal cirri and hooks are 

 directed upward. 



