NO. 1 HARTMAN : POLYCHAETOUS ANNELIDS 61 



slender teeth. The fourth parapodium is shown (Ehlers, pi. 15, fig. 3) 

 with a longer [postsetal] lobe and 2 shorter, nearly equal lobes, the low- 

 er presumably postsetal. The hooks in anterior segments were described 

 as "gedeckten Doppelhaken" ; from an examination of pi. 15, fig. 9, one 

 gets an impression that they are partly tridentate, but the artist obviously 

 failed to distinguish the hook from the hood. Branchiae are large, strong- 

 ly spiraled from the fifth to twentieth setiger, rapidly diminish thereafter 

 to the thirtieth, from which there are simple filaments, absent from about 

 the fiftieth segment. 



Ehlers' figures of anterior parapodia and pectinate setae agree so close- 

 ly with corresponding parts of specimens in collections from Peru, which 

 are designated D. obliqua, that their identity is strongly suggested. Botli 

 have the heavy anterior branchial region, the oblique pectinate setae, the 

 dentate limbate setae, and the same kind of anterior parapodia. They 

 differ, however, from what has been called D. chiliensis Quatrefages by 

 Monro (1933, p. 72) for specimens from the Pacific side of Panama. 

 Here the setal lobe of anterior parapodia is shown to be very different, 

 and the pectinate setae are not obliquely dentate at the distal end. Bran- 

 chiae are present from the fourth or fifth parapodium and continued pos- 

 teriorly to the sixtieth or seventieth segment. The setal lobes are much 

 more like those shown for D. amboinensis Willey (1905, pi. 4, fig. 96) 

 from Ceylon. 



Diopatra tridentata, new species 

 Plate 2, Figs. 37-43; Plate 17, Figs. 335, 336 



Collections.— 24^-3A (2); 273-34 (fragments); 429-35 (2); 588- 

 36 (1) ; 930-39 (1) ; 936-39 (1) ; 948-39 (1) ; 1030-40 (tubes) ; 1069- 

 40 (2); 1126-40 (3); 1130-40 (1); 1236-41 (1); A 14-39 (6, with 

 tubes) ; A 15-39 (8) ; A 38-39 (1) ; A 42-39 (2, with tubes). 



These specimens differ from other species of Diopatra most conspicu- 

 ously in having ( 1 ) tridentate hooks in anterior segments, (2) a uniquely 

 annulate, smooth tube, and (3) pigmentation pattern as described below. 

 Length of an anterior end of 50 setigers is about 55 mm. In some speci- 

 mens the prostomium has a small, black eyespot on either side, between 

 the bases of outer and inner lateral tentacles. The ceratophores of occipi- 

 tal tentacles are pale, annulate, the inner laterals the longest. Each has 

 8 to 10 rings, the distalmost ring about 3 times longer than the others. 

 The styles are long, the inner lateral one the longest, reaches back to 

 about the eleventh setiger. The styles are covered with coarse papilla- 

 tions in irregular arrangement, not in rows, and the papillae are all of 

 about the same size. 



