CORYNOCEPHALUS PAUMOTyVNUS. 141 



CoRYNocEPHALus Levinsen. 



Kongl. Danske vidensk. sselsk. Skrifter naturvid. math., 1885-86, 3, p. 327; Apstein, Ergebn. Atlant. 

 Ocean * * * Plankton-exped., 1900, 2, H. h., p 11. 



Of this genus one species, which is new, was secured, making the fourth 

 known. It may be placed by means of the following key: 



Key to Species. 



a. Somites distinctly bipartite on ventral side C. albomacidatus Levinsen. 



aa. Somites ventrally entire. 



b. Axes of eyes meeting at a right angle C. tenuis Apstein. 



66. Axes of eyes forming a straight transverse line. 



c. Median tentacle blunt, attached far in front of axes of eyes C. paumotamis, sp. nov. 



cc. Median tentacle slender, attached at or caudad of level of axes of eyes. . . .C. gazellae Apstein. 



CORYNOCEPHALUS PAUMOTANUS, Sp. nOV. 



Plate 23, fig. 1-3. 



The body at present is a dilute yellowish, excepting the segmental glands, 

 which are dark purplish brown; the eyes are also darker than the general body 

 and of a somewhat orange cast. 



The body consists of fifty somites in addition to the prostomium. The 

 total length is 28 mm. The greatest width, exclusive of the parapodia, is 2 mm., 

 and, inclusive of the parapodia, 3.7 mm. The body is flattened dorsoventrally. 

 It is widest in the middle region, from which it narrows to a point at the caudal 

 end, and also narrows strongly cephalad, the first somites being abruptly much 

 narrower than the prostomium, inclusive of the eyes. 



The prostomium is elevated between the eyes like a short half cy finder 

 placed transversely. A low, subcorneal projection on its anterior face represents 

 the median tentacle. In front of this elevated region is a depressed, subquadrate 

 lobe projecting in front of the eyes; the anterior corners are rounded and the 

 anterior margin is mesally a little incurved. This lobe projects broadly ventrad 

 of the general level and its plain ventral surface bears the four paired ten- 

 tacles. The paired tentacles are large, flattened, lanceolate, foliaceous struc- 

 tures, of which the posterior pair are the larger. On the anterior edge at the 

 base of each is a small dark spot. The eyes are large and project prominently 

 laterad, their axes lying in a common straight, transverse line. (Plate 23, fig. 1,2). 



Except at the extreme ends of the body, the somites are of nearly uniform 



