NO. 5 HARTMAN : POLYCHAETOUS ANNELIDS 503 



In typical median parapodia the notopodia are low, inconspicuous 

 mounds located at the dorsal base of the long dorsal cirrus ; they have a 

 few scattered epithelial papillae (pi. 61, fig. 4). Neuropodia are larger, 

 longer, compressed lobes with a well developed ramus and a prolonged, 

 triangular, postsetal lobe (pi. 61, fig. 5). In anterior and median para- 

 podia there is a minute, spherical papilla between notopodia and neuro- 

 podia, below the dorsal cirrus. This is collapsed in some segments. 

 Dorsal and ventral cirri are long, cirriform throughout the body but the 

 dorsal cirri are much the larger. Furthermore, in posterior parapodia 

 the proportionate lengths of dorsal and ventral cirri increases, the noto- 

 acicular spine comes to be larger and the neuropodial fascicle diminishes. 



Both notopodia and neuropodia in all parts of the body are provided 

 with single, yellow, translucent acicula; those in neuropodia are heavier, 

 terminating distally in a straight spine; those in notopodia are slender 

 and terminate distally in a bent point (pi. 61, fig. 7). The latter are 

 embedded in anterior segments but in median and posterior segments 

 they tend to project from the distal end of the lobe. The acicula are to 

 be distinguished from setae or spines since they extend farther into the 

 parapodial tissue and are probably the fulcrum from which setae and 

 spines function. 



Notoacicular spines are present through a long region to the posterior 

 end. They are visible in the fifteenth, but may be present in an earlier 

 segment. The first ones are small and embedded but by the thirtieth 

 segment they project slightly from the notopodial lobe. They increase 

 rapidly in size in median segments of the body and come to project for a 

 considerable distance in the posterior end (pi. 61, fig. 4). Their free end 

 is strongly recurved (pi. 61, fig. 6). 



Neuropodia are provided with only simple, pointed setae arranged in 

 spreading fascicles. They consist of shorter ones above and below and 

 longer ones in the middle of the fascicle. All are of a single kind, with 

 long, cylindrical shaft, a longer or shorter blade and distally pointed end 

 (pi. 61, fig. 8). The blade is knifelike, thinnest along the cutting edge, 

 with numerous oblique teeth in single series along the edge ; a shorter seta 

 is shown in Plate 60, fig. 8. A cross section along the blade shows an 

 elongate triangular structure with the short base of the triangle along 

 the back of the seta. The number of teeth at the cutting edge for a seta 

 from the fortieth parapodium varies from only 13 for the shorter ones to 

 as many as 25 to 28 for the longer ones. The distal smooth tip is nearly 

 one-sixth the total length of the seta, the dentate region comprises about 



