TEREBELLIDES EURYSTETHUS. 439 



The principal, or anterior, branches are large; anteriorly they extend antero- 

 ventrad of the point of attachment to the stalk ; the lamellae are large and 

 densely arranged. The posterior, or inner, branches are free a shorter distance 

 than in stroemi. They are less attenuated distad, the end being bluntly rounded 

 and having a short, slender filament. 



The first segment is prominent ventrally and laterally; it is widest on the 

 sides; ventrally it presents two deep, submedian, longitudinal sulci. 



The second somite is also prominent, being carried ventrad nearly as far as 

 the first; ventrally it is of nearly the same length as the first, but it narrows 

 laterally instead of widening. 



The third somite is of nearly the same length ventrally as the second, and 

 is of uniform length throughout. The fourth and fifth are narrower ventrally 

 and wider laterally. The succeeding somites to the tw^elfth setigerous are much 

 shorter ventrally than the anterior ones and wider up the sides. The other 

 thoracic somites, which are in the much narrower caudal division of the body, 

 are much more elongate; ventrally, in line with the parapodia, they bear con- 

 spicuous, thickened, light-colored, glandular tori. 



The abdominal somites decrease in length gradually caudad, the last 

 twenty to thirty being especially short and closely arranged; the last few somites 

 narrow rapidly, making the caudal end round in conspicuously to the small 

 pygidium. 



The first notopodia are short and rounded ; the others are longer, but remain 



throughout the broad division of the thorax relatively short and stout, subcylin- 



, drical and distally rounded; those of the narrow division of the thorax are of 



same proportion, excepting the most caudal, which are somewhat more slender. 



(Plate 80, fig. 9). 



The uncinigerous tori begin on the sixth setigerous somite, as usual. 



The pinnulae of the abdomen are prominent. Those of the posterior half 

 present distally a prominent, caudoventral process and a less prominent, cephalo- 

 dorsal one, the distal end expanding over the base. (Plate 80, fig. 8). On the 

 anterior abdominal somites these pinnulae are shorter. (Plate 80, fig. 7). 



The capillary setae of the first somite are shorter and finer than the others. 

 In general, the setae are obviously coarser than in stroemi and are constantly 

 a little bent toward the distal end. The wing of one side is much wider than 

 usual in stroemi. (Plate 80, fig. 10). 



The thoracic uncini have the long, distally somewhat curved stalk, as usual; 

 the neck is not especially pronounced, the stalk below the head being but little 



