208 THE ANNELIDA POLYCHAETA. 



one side. The neurocirrus is smaller than the notocirrus and similarly slender. 

 It bears the usual lamina on each side of its base. (Plate 33, fig. 2-4). 



The acicula are two and have the ordinary form and coloration, black or 

 nearly so, excepting for a colorless proximal portion. Only the notopodial acic- 

 ulum is normally developed in the anterior four pairs of parapodia. Acicula 

 of the nereid division in general are notably smaller and less conspicuous than 

 those of the natatory parapodia. The setae of the anterior parapodia are of 

 thi-ee types. First, homogomphs, with long, slender, tapering end pieces with 

 fine smooth tips above the marginally setose portion. Second, heterogomphs, 

 much less numerous, which have similar end pieces, but these shorter, and especi- 

 ally so the tips. And third, heterogomphs with shorter end pieces having a 

 short, narrowly rounded tip above the broader portion that is setose along one 

 edge. The shafts are striate as usual. The notopodial setae of the anterior 

 parapodia, of which none at all seem to be present in the first several pairs, are 

 when present, fewer in number than the neuropodials and are shorter and finer. 

 They are homogomphs, otherwise like those of the neuropodium, but with shorter 

 terminal blades. The natatory setae of both neuropodia and notopodia are 

 numerous and of the ordinary type. They are homogomphs with double, striated 

 bands in the shafts, wdth oar-like terminal blades widening distad and ending in 

 a mucronate apex, and with very fine teeth of uniform character along one side. 

 (Plate 32, fig. 6-8; Plate 33, fig. 5-6). 



The proboscis is but slightly protruded. The paragnatha are separate, 

 small, corneus cones of the Nereis type. The maxillae are large, with teeth coarse 

 and distally blunt. 



Locality. Marshall Islands: off Rongelab Island. Surface by night light. 

 17 January, 1900. One male. 



This species may be characterized by the form of the prostomium and 

 the position and size of its eyes and palpi ; the transversely divided peristomium 

 in which the anterior division is not angularly extended forward; the short 

 tentacular cirri, of which the longest reach only to the fifth somite; the number 

 of somites in the nereid division, sevente.en, with specially modified cirri on only 

 the fii'st five pairs, and with no neurocirri strongly modified, only the first two 

 pairs being at all noticeably different; and the small size of the laminae of the 

 natatory setae. 



