HESIONE GENE^rTA. 187 



The general color is an iridescent grey of slight yellowish cast. The dorsum 

 of each segment is characteristically marked with dots of deep violet color. 

 The dots on the first segment ordinarily are numerous and closely arranged 

 or confluent in a transverse band across the caudal half. On the other seg- 

 ments there is a triangular patch on each side between the dorsal sulcus and the 

 parapodium, the point of the area being ventrad and a little above base of para- 

 podium. On each somite between the sulci the dots are nearly absent from the 

 anterior half, or with but a few scattered ones present, but form a continuous 

 series across the middle in which the median one is often largest, while in the 

 posterior part the dots tend to leave the series open at the middle and to be 

 largest at the lateral ends. The number of series of dots on each somite is 

 ordinarily three or four, not including the scattered ones present in the anterior 

 region of some. In one small specimen on each somite there is but a single spot 

 on each side above the parapodium and three transversely elongate marks on 

 the dorsum, or these may practically unite into a single transverse stripe. In 

 the smallest specimens there is a solid stripe across the first segment in place 

 of the band of segregated spots of the larger ones. Also on succeeding somites 

 there is but a single series of marks. The marks tend to fade out on the pos- 

 terior somites. The venter in all is wholly without dark marks. 



Parapodia subcylindrical, distally truncate. The neurocirri usually extend 

 near or a little beyond the tips of the setae. The notocirri are long, clearly 

 exceeding the width of the body and the longer ones equal in length to the longest 

 dorsal tentacular cirri, which extend back to the middle of the sixth parapodia- 

 bearing somite. The anal cirri in length about equal to the longer tentacular 

 cirri. 



The prostomium is much narrower than the succeeding somite, strongly 

 narrowed forward, triangular in outline, with the apex rounded and the sides 

 more or less bulging in such way that the caudal portion may appear subquad- 

 rate, the narrowed anterior portion depressed. In the smaller specimens the 

 prostomium appears more subquadrate; with two short, moderately acuminate 

 tentacles, one arising on each side from a slight notch a little caudad of the 

 anterior end. The caudal margin of prostomium may be distinctly notched. 

 A median longitudinal furrow extends forward from this notch to a distinct, 

 transverse, arcuate sulcus extending between the two posterior eyes and with its 

 convexity forwards, and continues to a second transverse sulcus between or a 

 little in front of the anterior eyes. From the latter transverse sulcus two sulci 

 run forwards and are connected so as to form a small subquadrate area and then 



