HYALINOECIA TECTON. 311 



longitudinal dorsal stripe of dark red color. The type-specimen, from Sta. 3425, 

 is much darker throughout; the dorsum anteriorly is a dark brown; but in the 

 middle and caudal regions this darker color becomes denser and restricted to 

 two longitudinal bands, leaving a pale band on each side and a wider median 

 pale band embracing the geminate, interrupted, median stripe. The venter is 

 brown anteriorly, becoming denser caudad, with a narrow pale stripe along bases 

 of the parapodia over the glandular areas, the parapodia themselves being also 

 paler. 



The body above is evenly convex, caudally becoming more depressed and 

 with a distinct shallow and wide furrow along each side just within the para- 

 podia, and a weaker depression along the middorsal ridge. The venter is less 

 convex, and has a distinct median longitudinal furrow which deepens caudad. 

 The body is deepest a little in front of the middle and becomes conspicuously 

 thinner, flattened, from there toward the ends. The maximum width is attained 

 near the middle and varies but little from there caudad except at the very end, 

 though some specimens increase in width to near the caudal end. A specimen 

 68 mm. long has a maximum width, exclusive of parapodia, of about 8.2 nun. 

 and a maximum depth of 6.6 mm. The largest specimen from Sta. 3424 is 75 

 mm. long. The type is 75 mm. long, with a maximum width of about 8 mm. It 

 is more strongly flattened caudally and less so anteriorly than above noted. 

 Number of somites seventy-six to ninety. 



Prostomium somewhat trapezoidal, but with the angles rounded. Anterior 

 margin convexly rounded and the caudal margin widely convex; the sides straight. 

 The median and both pairs of lateral tentacles situated on the posterior half 

 of the prostomium, the anterior laterals being attached at the edges but little 

 cephalad or directly ectad of the posterior laterals, and with the latter and median 

 tentacle, forming a sHghtly curved row. In this row the ceratophores decrease 

 in thickness and length from the median to the most ectal on each side; cera- 

 tophores rather obscurely ringed, sometimes constricted about the middle so as 

 to give two large and equal rings, with a less evident constriction above and below 

 this, giving two adjacent median rings which are short and two larger terminal 

 ones, or in other cases four more nearly equal annuli may be traced. Median 

 tentacle reaching somite XV, posterior laterals XII, and the much shorter 

 anterior laterals IV. The frontal tentacles very short, considerably less than 

 half the length of the prostomium, subelliptic in outline, more than half as thick 

 as long, strongly divergent and directed somewhat ventrad. Palpi rounded, 

 elevated, strongly rugose. 



