848 PROCEEDINGS OF THE ACADEMY OF [DeC, 



The tubercles of IV and V are crowded closely together beneath the 

 lateral margins of the branchial scars, that of the latter being slightly 

 medial and caudal of the other. Both, and especially the latter, are 

 minute. Succeeding tubercles up to the sixth increase in size, after 

 which they remain of constant size and of a slightly flattened cylin- 

 drical form. Distinct, more or less club-shaped cirri are borne on the 

 ventral side of the distal portion of all the tubercles, but they are larger 

 and more abruptly clavate on the first four. The first and second tufts 

 contain only six or eight sets, the others twelve to fifteen, always 

 arranged in two rows. 



The uncinigerous tori are distinct, somewhat ear-shaped lappets aris- 

 ing from the posterior border of the segments below and separated by 

 a short space from the setigerous tubercles. The anterior ones are the 

 longest and their ends project most freely. Their size decreases regu- 

 larly to the last thoracic. The uncini form a single irregularly curved 

 line containing 160 to 170, which are largest dorsally and decrease reg- 

 ularly to the ventral end. 



Abdominal somites are provided with shorter tori (fig. 2) which pro- 

 ject more prominently than those of the thoracic segments. They bear 

 about 75 uncini in a single series. No trace of ventral cirri can be 

 detected, but the achcetous notopodia are provided with prominent, 

 curved, paddle-shaped cirri. 



The paleoli form rather close spreading tufts, with the largest ones 

 near the anterior margin but not reaching to the tip of the prostomium. 

 They (fig. 3) are much flattened and moderately stout at the base and 

 taper rather abruptly to acute tips. They are bright yellow and pol- 

 ished. The setae are pale yellow, strongly striated, slightly curved, with 

 narrow double wings and very acute tips. On the first three somites 

 they are rather more slender than on the others. 



The uncini (figs. 4a to c) are more or less triangular, with the upper 

 rounded portion much elevated, the posterior ligament process very 

 prominent, and the anterior one small and covered by the lowermost 

 hook. The base is relatively short. The relative breadth to length 

 varies. Usually there are six large, acute, closely appressed teeth or 

 fangs, the clefts between which do not incise the base very deeply (less 

 than one-half of the entire width of the uncinus). Frequently the 

 upper tooth is much reduced in size. 



The type of this species was taken with one other specimen at station 

 4,274, in Kadiak Bay, at a dej^th of 41 fathoms on a bottom of green 

 mud with some fine sand. Another and larger one comes from Boca de 

 Quadra, Southeast Alaska, in 48 fathoms and soft green mud. 



