188 PEOCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



regular, defined by clear-cut furrows and increasing somewhat 

 in relative length to the middle, where they are three to three and 

 one-half times as wide as long. 



Pygidium a minute, slightly compressed, simple ring with the 

 ventral border somewhat produced and the anus a vertical slit. 



Prehensile tentacles borne on dorso-lateral region of first setig- 

 erous somite immediately above and anterior to the notopodia 

 and beneath the border of the nuchal cope. They are grooved for 

 the entire length, smooth, slender and filamentous and in length 

 probably equal one-half the length of the worm, though owing to 

 their much coiled condition, exact measurements cannot be made. 



Branchial filaments nearly as long as the tentacles but much more 

 delicate, arising immediately at the dorsal margin and slightly 

 behind the notopodia. They apparently occur on every setigerous 

 somite except the first and about the last twenty. 



Parapodia consist of minute, scarcely elevated notopodia and 

 neuropodia separated by a slight interval. Notopodia bear a 

 small tuft of very delicate colorless capillary setae, those on the 

 middle segments being nearly as long as the diameter of the worm. 

 Neuropodial setae (Plate XVII, fig. 2) in a transverse series of 

 seven to twelve, dark colored and except at the anterior end much 

 stouter and not more than j or ^ as long as the notopodial setae. 

 Alternating with the acute setae are short blunt ones. 



Color pale buff with a faint pearly irridescense anteriorly. 



Type complete, 110 segments, 29 mm. long, 1 mm. diam., 9 

 filled with opake eggs. 



Station 4397, off Santa Catalina Islands, 2196 fathoms, gray 

 mud, (type); 4430, off Santa Cruz Island, 197-281 fathoms, black 

 sand, (cotype). 



Acrocirrus crassifilis sp. nov. Plate XVII, figs. 3-7. 



Prostomium and peristomium (Plate XVII, figs. 3, 4) completely 

 coalesced to form an obliquely annular head, opening by a large 

 mouth directed ventrad and forming a convex dome-like over- 

 arching lip above, which, however, projects little beyond the mouth. 

 Prostomium a convex rhomboid area, the anterior angle of which 

 ends in a narrow, strongly compressed vertical ridge lying between 

 the bases of the cephalic tentacles and reaching ventrally to the 

 anterior margin of the mouth. At its dorsal end, the ridge bifurcates 

 into a pair of raised lines which skirt the anterior borders of the 

 prostomium to its lateral angles. These angles are completely 

 occupied by a pair of remarkably large eyes having a diameter of 

 fully one-fourth the width of the prostomium. These eyes are 

 directed forward and immediately behind them and in line with 

 their medial borders, so close indeed as to be in contact with the 

 large eyes and distinguished from them with difficulty, is a pair 

 of minute eyes directed caudad. A faint white line passes trans- 



