COMPLETE HARTMAN: POLYCHAETES FROM CALIFORNIA 119 



The prostomium is a small, inconspicuous lobe with 4 large eyes. 

 It is surrounded by a tentacular membrane with 50 or more oral 

 tentacles, all similarly long and filiform. The paired palpi are much 

 thicker, slightly shorter, inserted ventrolateral to the oral slit, and held 

 side by side (PI. 22, fig. 2) in contracted condition; they are probably 

 capable of great extension in life. The cephalic cage surrounds the 

 anterior end like a collar directed forward. 



The setae of the first segment are numerous and continued as a collar 

 about the anterior end. They comprise the notopodial and neuropodial 

 setae in linear series; all are of one kind, long, slender, hairlike and 

 internally crossed by striae. From the second segment the notopodial 

 setae are in discrete fascicles and shorter, directed laterally. Seen in- 

 dividually (PI. 23, fig. 2) they are crossed by striae. Neuropodia from 

 the second segment are ventral in position and provided with one or 

 seldom two large, f alcigerous hooks in a fascicle ; they are accompanied 

 by 3 to 5 very slender, inconspicuous, distally pointed companion setae 

 (PI. 23, fig. 1); the latter are uniformly slender along the shaft and 

 taper abruptly to slenderer tips in their free portion. Seen individually, 

 the hooks are sharply recurved at the tip and dark brown to nearly 

 black, whereas the shaft is translucent. The articulation is incomplete, 

 best seen on the convex side (PI. 23, fig. 1). The embedded shaft is 

 internally cross-striated, and the region beyond the articulation is ob- 

 liquely striated on its surface. 



Epithelial papillae are of 2 or more kinds. Those of notopodia are 

 most easily seen. They can be dissected out of the enveloping notopodial 

 sheath, along with the notopodial setae and investing membranes (PI. 

 23, fig. 3). The most conspicuous are very large, long-stemmed, balloon- 

 like structures attached to a long, slender filament ; they range from 

 large, long-stemmed, to much smaller, short-stemmed. Seen under high 

 magnification the stalk can be seen penetrated by a canal extending to 

 the inflated base; the balloon is entirely canopied by large pavement cells, 

 whereas the inner space is clear and watery. The 2 largest of these 

 structures are usually seen emerging from upper and lower ends of the 

 notopodial sheath (PI. 23, fig. 4), and the smallest are near the base 

 of the notopodium. They are believed to be continuously developing, 

 increasing in size and length as shown in the figure. 



The other kind of notopodial papillae is slender, bottle-shaped, all 

 of similar size but with shorter to longer stalks. They are in dispersed 

 arrangement about the notopodial base and among the balloon-like 



