258 PROCEEDINGS OF THE ACADEMY OF [April, 



rarely two, very slender, almost fibre-like, tapered and reaching nearly 

 to tip of cirrophore. All acicula pale yellow. 



Setae perfectly colorless and vitreous, of two kinds: simple supra- 

 acicular and compound subacicular. The former (PL VIII, fig. 25) 

 number 15-20 on anterior parapodia, and become gradually fewer and 

 stouter posteriorly until they are reduced to a single rather stout one. 

 They are gently curved, slightly tapered and faintly fringed along 

 the convex side, and terminate rather abruptly in a small blunt hook 

 which is embraced between a pair of guards difficult to observe on 

 the more slender seta?, but sufficiently obvious on most of the stouter 

 ones. Compound setae form an oblique spreading tuft of twenty to 

 thirty on anterior and about one-half as many or even fewer on pos- 

 terior segments. The stems (fig. 24) are gently curved, slightly 

 enlarged and obliquely truncate distally, and just perceptibly den- 

 ticulated on the convexity. Appendages subtriangular, their length 

 two or three times the distal width of the shaft, tapered to the promi- 

 nently hooked tip, below which is a conspicuous accessory tooth, the 

 whole protected on one side by a very delicate, minutely denticulated 

 guard. 



The jaws of only one specimen were dissected. The smallest ones 

 are deep brown, the others black and opaque. Mandibles (fig. 26) are 

 heavy, with forcep-shaped bases and massive end-plates, the convex 

 margins and ends of which bear a series of blunt teeth and are much 

 broken with use; a thin chitinoid streamer containing two or three 

 black nodules is appended to the lateral side of the tip and the two 

 plates are lightly jointed medially. Maxillae form two long bands 

 extending through about eight segments and borne on the dorsal face 

 of a thick muscular pad. They are slightly united behind and each 

 consists of three series of denticles of about thirty-five or forty each, 

 besides a posterior tract where the separate denticles of each series 

 have coalesced. All free denticles have more or less deeply cleft 

 V-shaped bases, and those at the anterior end of each series are most 

 complex, hooked and slender. The inner series consists of small 

 denticles (figs. 29a and b), the anterior members of which have a pair 

 of long, subequal, acute teeth often flanked by smaller ones; passing 

 caudad the lateral teeth disappear and then one of the large teeth, 

 leaving a series of one-toothed plates that soon unite into a serrated 

 band. Jaws of the outer and middle series are much larger; the outer 

 ones (fig. 27) with strongly curved stems and several acute teeth 

 arranged asymmetrically near the end; several of the most anterior 

 are very slender, strongly falcate and nearly simple, but they soon 



