1909.] NATURAL SCIENCES OF PHILADELPHIA. 247 



subsequent segments indicates that it probably occurs at CCX, though 

 eye-spots of smaller size appear abruptly at CLII. 



The epitokous region is very slender, subterete or slightly depressed, 

 with a well-defined neural groove and distinct furrows separating 

 segments generally about three times as wide as long. Surrounding 

 each segment in the parapodial zone is a raised glandular band, some- 

 times single but oftener formed of two lines. Posteriorly the body 

 tapers and is composed of numerous very small segments — evidently 

 a rapidly proliferating region. The ventral eye-spots form a neural 

 series of usually two spots to each segment: one on the glandular 

 girdle, the other at the intersegmental furrow, sometimes one, some- 

 times the other being larger and frequently one or both subdivided. 



Pygidium tubular and somewhat elongated, obliquely truncated 

 with the small anus facing dorsad; posterior to anus two pairs of 

 conical caudal cirri, of which the dorsal pair is about as long as the 

 diameter of the pygidium and nearly three times the ventral. 



Parapodia uniramal. Typical parapodia of the anterior region 

 consist of a short, broad, truncate neuropodium, bearing a low post- 

 setal fold behind the compound setae and a small presetal lobe in front 

 of the simple setae. The simple notocirrus springs without a cirro- 

 phore from above the neuropodium and is a bent, slightly tapered 

 blunt process reaching a short distance beyond the distal end of the 

 foot. Neurocirrus consists of a low glandular elliptical cirrophore 

 adnate to the side of the segment ventral to the parapodium and 

 bearing a small, blunt, cylindroid or conical style. Farther back all 

 parts and particularly the cirri are gradually reduced in size. The 

 first parapodium (on III) has the setigerous lobe rudimentary, bearing 

 only two or three setse, and consists chiefly of a simple notocirrus and 

 neurocirrus nearly in contact, the former shorter and stouter, the 

 latter about twice as long, more slender, obscurely articulated and 

 more or less bent into a bow. Several succeeding parapodia are 

 transitional to the typical form, springing from a gradually rising level, 

 the neuropodium gradually increasing in size and the cirri becoming- 

 smaller. In the epitokous region the entire foot is much smaller, the 

 neuropodium a conical process whose outlines pass into the dorsal and 

 ventral curvatures of the segments, the notocirrus a minute conical 

 process above the foot and at the base of the gill, and a similarly formed 

 neurocirrus arising from a thick glandular ventral area or cirrophore. 



Gills appear as a pair of minute papillae on the medial side of the 

 base of the notocirri of CVII and increase in length gradually until 

 they become slender tapering filaments having a length of one-half 



