272 PROCEEDINGS OF THE ACADEMY OF [April, 



a,t least one compound crochet persists to the eighth foot and three 

 to the seventh. They are rather slender, with well-developed articu- 

 lation and distal pieces that vary much in length (figs. 61 and 62) the 

 longest being dorsal, the shortest ventral. They end in a slender, 

 acute, strongly hooked tip, beneath which are two prominent and acute 

 spurs, the whole enclosed in a split guard closely fitting the terminal 

 hook and scarcely prolonged beyond it. Simple, acute setae are 

 represented by one or two small ones on the first and second parapodia, 

 but are not clearly distinguished from the acicula, above and behind 

 which they lie. Farther back they become more numerous, longer, 

 much more slender, and finally even the very narrow limbus that they 

 present anteriorly disappears. On posterior parapodia the fascicle 

 is composed exclusively of six or eight setae of this type. In the 

 subacicular region the articulated crochets are replaced by short, 

 rather broad, acute setae, more or less distinctly articulated (fig. 63). 

 Such setae continue to between somites XV and XX. The larger 

 articulated crochet which appears in the acicular process of anterior 

 parapodia seems to persist, become stouter, lose its articulation and 

 gradually its terminal hook (fig. 65), thus becoming converted into a 

 simple bidentate hooded crochet similar to those occurring on pos- 

 terior segments. This transition is well shown up to somite XV of 

 the mounted cotype. Apparently, however, there is a gap between 

 the last of these and the first of the posterior simple crochets, two of 

 which appear together ventral to the acicula at about somite XX of 

 these specimens. Unlike the anterior crochets, they project only 

 slightly. They are deep yellow, stout, bifid, with the main tooth below 

 and have the end enclosed in the usual cleft hood (fig. 66). Pectinate 

 setae (fig. 64) occur in the dorsal fascicle of most segments, but their 

 exact distribution was not determined. They are very delicate, with 

 the widened end very little curved and bearing only a small number 

 of rather long processes. 



Jaws described from a single dissection. Mandibles (fig. 67) soft 

 and thin, the carriers nearly colorless with a black streak distally, 

 narrow, of nearly uniform diameter, lightly united at the distal end; 

 masticatory plates white, irregularly trapezoidal, each divided by a 

 deep anterior notch into two large teeth, each of which is again notched. 

 Maxillae (fig. 68) thin, very pale brown with narrow deep brown 

 marginal lines and thickenings; carriers of forceps-jaws as wide as long, 

 shield-shaped, with straight transverse hinge line; basal half of forceps 

 thickened, distal slender, regularly tapered, moderately curved and 

 acute. Maxillae II large, subtriangular plates, each of the three bearing 



