NO. 5 HARTMAN : POLYCHAETOUS ANNELIDS 507 



that their structure is difficult to ascertain but by slightly depressing the 

 prostomial lobe they can be made to move forward. The peristomium or 

 first segment is a simple, smooth ring, shallowly emarginate at its anterior 

 dorsal edge where it meets the prostomium. It is somewhat longer than 

 the next, or first, setigerous segment. 



The proboscis is large, cylindrical, eversible and somewhat clavate 

 when not completely everted. It terminates distally in a vertically open 

 slit, bounded by an inner series of 4 smaller papillae on each side and by 

 an outer series of 4 much larger ones on each side, or a total of 8 smaller 

 within and 8 larger ones without. There are no jaws or comparable 

 embedded structures within the tissue of the proboscis ; examination was 

 made by dissection using both transmitted and reflected light. The 

 proximal surface of the proboscis is smooth and glistening. When it is 

 retracted it extends back through the tenth setigerous segment. 



The first 5 setigerous segments are inflated and the surface epithe- 

 lium is weakly areolated. The parapodia in this region (except for the 

 first 2 pairs) are larger than those farther back and they lack dorsal or 

 ventral cirri. The lobes are merely elongate, oval, and the setae emerge 

 from them. Segmental grooves in this region are deep at the sides, 

 between successive parapodia but much less distinct on ventral and dorsal 

 sides. Farther back the epithelium is smoother and the segmental grooves 

 more distinct. In addition, the segments are biannulate, the 2 rings sub- 

 equal and the posterior ring is parapodial. Under magnification each of 

 the 2 rings is seen to be traversed by many fine, transverse rings as though 

 the segments were capable of considerable extension in life. 



The second, or first setigerous, segment is provided with uniramous 

 parapodia but all subsequent ones are unequally biramous, with smaller, 

 papillar notopodia and larger, longer neuropodia. The first parapodium 

 resembles a neuropodium farther back but it takes the dorsal position of a 

 notopodium. It is an elongate, oval lobe, provided with a single yellow 

 aciculum near its middle, and 5 transverse series of long, pointed setae 

 that emerge posterior to the aciculum. These 5 series of setae consist of 

 3, 4, 4, 2 and 2, from dorsal to ventral ends or a total of 15 setae. 



The third, or second setigerous, segment has biramous parapodia. The 

 notopodium is minute, represented only by a tiny, low papilla ; it is pro- 

 vided with single yellow acicula and a small tuft of 4 pointed setae. Its 

 aciculum is embedded save for a very short, free tip. The neuropodium 

 is similar to that of the first segment but larger and longer; its setae are 

 more numerous but they have an arrangement similar to that in the first. 



