'252 PROCEEDINGS OF THE ACADEMY OF [April, 



of a massive irregularly twisted base, from which arises a tongue-like 

 piece the end of which is strongly flattened at right angles to the great- 

 •est thickness of the base and terminates in a fringed tip, from the 

 central cleft of which arises a slender, densely hairy process (fig. 46). 

 These paleoli are so arranged that they present a spreading rim, in 

 which their twisted form causes the basal portions to be somewhat 

 imbricated from below dorsalwards. 



The middle paleoli number from 14 to 25, usually about 20, in sym- 

 metrical halves. They (fig. 45m) also have a thickened base, from 

 which arises a very prominent upright spine, gracefully curved and 

 tapered to an acute tip. The inner circle of paleoli contains from 14 to 

 22, but in nearly all cases they equal and alternate with those of the 

 middle row. They (fig. 45i) have abruptly widened cleaver-shaped ends 

 bearing a knife-like edge and strengthened on the opposite side by a 

 thickened rim which ends in a short triangular beak. They are dis- 

 posed somewhat obliquely to the middle line and converge ventrally. 



Somite II bears a small tuft of strongly doubly-fringed, feather-like 

 neuropodial setae (figs. 49 and 50). On III the neuropodial setse are 

 partly of a short, more brush-like form and partly very small and of a 

 slender, slightly fringed form. On the remaining thoracic segments 

 they all become more sparsely fringed. The notopodials (fig. 47) on 

 III, IV and V form a single vertical series of stout setse, shaped like 

 an Indian paddle with the end much split and frayed. At the base of 

 each of these is a minute spatulate hairy setse, with the end entire and 

 somewhat produced in the middle, and the blade bent flatways. 



Abdominal setse are all very long and slender, but owing to different 

 states of development appear of unequal length. Their shafts (fig. 

 48) are provided with numerous whorls of hairs united at the base 

 into collars and much produced on one side. 



The uncini (fig. 51) are very numerous and vary from 100 to 200 or 

 even more on a torus. They are nearly colorless, delicate and incon- 

 spicuous, and consist of narrow elongated bodies provided with from 

 7 to 9 (seldom the former) very acute, appressed, overlapping teeth 

 which are arranged in one series and diminish in size toward both ends. 

 Each bears a stiff and rather brittle tendon at each end, the upper one 

 being short and expanded distally into a small plate, while the lower 

 bifurcates immediately into a shorter, irregularly thickened, more ven- 

 tral branch and a slender uniform branch greatly elongated to many 

 times the length of the uncini. 



This species is probably rather common and occurs in the collections 

 from the following stations: 4,220 (type). Admiralty Inlet, near Port 



