320 THE ANNELIDA POLYCHAETA. 



This genus seems unquestionably close to Hyalinoecia. From this it differs 

 especially in wholly lacking branchiae, and in the much greater relative length 

 of the peristomium, which the first parapodia do not surpass. 



Leptoecia abyssorum, sp. nov.^ 

 Plate 36, fig. 1-6; Plate 37, fig. 1-8. 



The general color is dull yellowish. There is a whitish, median ventral, 

 or neural line. The parapodia are a lighter yellow and the tentacles, cirri and 

 ventral glandular areas are pale. 



The type is a slender specimen in three fragments which have a total of 

 about seventy somites. The fragments together have a length of about 42 mm. 

 The width does not vary much excepting at the extreme caudal end, where the 

 body narrows to a point. The anterior end is not narrowed. The width in 

 the middle region of the body is 1.75 mm. 



The prostomium is narrowed from behind cepbalad, being bluntly subconi- 

 cal. Anteroventrally the prostomium presents four lobes, being divided by 

 a median subvertical furrow and again by a transverse furrow. The upper 

 lobes are essentially frontal tentacles; they are low and rounded, subhemi- 

 spherical, and pale in color. The lower lobes are larger and correspond to the 

 palpi, e.g., in Onuphis. They are large, smooth, thick rounded pads on the 

 ventral side. They are contiguous at the middle line and extend transversely 

 to, or bulge out a little beyond, the lateral borders of the prostomium. The 

 anterior paired tentacles do not reach the caudal end of somite I. The cerato- 

 phore is short and but vaguely annulate. The style is proximally as thick as 

 the ceratophore and narrows distad to the free end. The posterior paired 

 tentacles are inserted caudoventrad of the anterior paired ones. They have 

 the distal portion of their styles broken off, so that their length camiot be given. 

 The ceratophore is only indistinctly annulate. The style at base is as thick 

 as or a Httle thicker than the ceratophore and narrows gradually distad, as usual. 

 The median tentacle is inserted but Uttle caudad of the level of the posterior 

 paired ones from each of which it is farther removed than the latter is from the 

 corresponding anterior paired tentacle. It is removed from the caudal edge of 

 the prostomium by its diameter, or more. Its style is broken off. The cerato- 

 phore is vaguely annulate and is thicker than that of the posterior laterals. 



(Plate 36, fig. 1, 2). 



1 abyssus, depth. 



