226 THE ANNELIDA POLYCHAETA. 



whole subulate, with no abrupt contrast between proximal and distal halves. 

 The most anterior parapodia are very short in comparison with their height. 

 They increase in length and stoutness caudad, those in the posterior portion 

 of the anterior division being unusually thick and distended with ova. The 

 neuropodium has one distinct Hgula, the notopodium two. These in the first 

 few pairs are slender, but soon become thick and blunt. In the heteronereis 

 division the parapodia are longer and much thinner and flatter in the cephalo- 

 caudal direction, with the ova extending into them not at all or only an occasional 

 one or two in the extreme base. Aside from the transformation of the setae into 

 the larger paddle-formed swimming type, these parapodia are conspicuously 

 different in their thin, membranous or foliaceous appendages, which in general 

 are like those of the male. 



The acicula and setae are essentially as in the female. The tips of the longer 

 anterior setae seem to be, as a rule, less prolonged. (Plate 30, fig. 5-8; Plate 31, 



fig. 10). 



The maxillae are larger and broader than in the male. Each is curved 

 ventrad as well as mesad. Distally comparatively wide and blunt. The mesal 

 edge armed with seven to ten low obtuse teeth, which at the distal end of the 

 series may appear as but slight undulations of the edge. (Plate 31, fig. 3). 



Localities. Ellice Island: Funafuti. Surface of lagoon, at 8 p. m. 24 

 December, 1899. Five females and thirty males. 



Gilbert Islands: off Arhno reef . Surface by night light. 21, 24 January, 

 1900. One male on the former date, and five males and one female on the latter. 



While the two sexes of this species are very similar in general color, in the 

 fine purpHsh markings, and in general appearance, as well as in the structure 

 of the setae and the armature of the proboscis, they present very striking second- 

 ary differences in various other structural details. The prostomia are alike 

 in having the characteristic transparent preocular lobe; but in the male it is 

 greatly longer, with the tentacles very much shorter and the palpi conspicuously 

 modified. The differences in the number of somites in the nereid division and 

 in the structure of the parapodia, particularly of the cirri, are marked. The 

 structure of the natatory setae, as well as of the simple notopodials, and the 

 form of the prostomium and its structures seem to be especially characteristic 

 in this species. 



