90 Bulletin Vanderbilt Marine Museum, Vol. VII 



this species. Lack of material for comparison leaves the matter 

 unsettled. The "Alva" specimen, from Tahiti, appears to be the 

 second record of P. gracilis from the type locality. 



Material examined: One specimen, taken on Venus Point 

 Reef, Tahiti, Society Islands, August 15, 1931. 



Technical description : The colour of the entire specimen 

 and its appendages is a rich deep black with an opalescent green- 

 ish-blue iridescence when wet. 



The head, which is dorsoventrally compressed as usual, is cor- 

 date, is one millimeter wide proximally and 0.9 millimeters long 

 and has the posterior margin sinuate, the free margin convex and 

 narrowed anteriorly ; the dorsal surface convex, with two sinuate 

 separate small furrows, one each extending posterior from be- 

 hind the submedian tentacle, the two furrows defining a narrow 

 median area on the dorsad of the head, which appear to be normal 

 and not due to death, etc. The dorsal posterior margin of the head 

 is sinuate, being slightly produced and concave in the median area 

 and curved forward convexly on either side. The first or anterior 

 pair of tentacles is the longer of the two pairs, being about 0.7 

 millimeters long and as thick proximally as long, distally tapered, 

 extending beyond the head, along its lateral margin, almost to the 

 posterior border. The second pair of tentacles is immediately pos- 

 terior and slightly dorsad to the first pair, but is only 0.5 milli- 

 meters long, thick proximally, but more abruptly tapered distally. 

 The one pair < tf eyes is situated in the median lateral area, being 

 separated well. Each eye is a large, subcircular, elevated, convex 

 black organ, with the visual range chiefly laterodorsad. 



The body is very long, slender, and much tapered posteriorly. 

 There are about four hundred and fifty-six somites present, the 

 hinder portion of the specimen being unfortunately broken off. 

 The width of the anterior portion of the body, measured about the 

 fifth somite, exclusive of the parapodia, is 1.5 millimeters wide, 

 about the two hundred and twenty-fifth somite it is 1 millimeter 

 wide and about the four hundred and fiftieth somite it is only 0.8 

 millimeters wide. The somites are quite convex dorsally. The 

 venter is flat with a distinct neural furrow which is more promi- 

 nent anteriorly. The specimen measures about 185 millimeters 

 long; broken. 



The parapodia are uniramous, lateral, well developed in depth, 

 almost attaining the vertical diameter of the body anteriorly and 



