144 THE ANNELIDA POLYCHAETA. 



Rh3Tachonerella, which must follow its type-species. Greeff's species capitata 

 (= fulgens), though apparently without a genus, is without doubt fully con- 

 generic with Plotohelmis alata, sp. nov. Rhynchonerella longissima of Levinsen, 

 as genera are now accepted, stands as Vanadis longissima (Levinsen). 



Plotohelmis alata, sp. nov.^ 

 Plate 23, fig. 4-10; Plate 24, fig. 1-3. 



The general color of the body at present is somewhat ferruginous, paler 

 caudad. The parapodia and cirri are pale yeUow. 



The body is long and thread-like, narrowing caudad and becoming very 

 slender or fine in the posterior region. Two fragments, apparently together 

 forming one complete specimen, have a total length of approximately 56 mm. 

 At present the maximum diameter, exclusive of parapodia, is only about .5 mm., 

 but as the specimen has manifestly undergone shrinkage as though from drying, 

 the width in life was probably considerably greater. The width, inclusive of 

 the parapodia, is 2.4 mm., and to the tips of the setae, 3.4 mm., the parapodia 

 at present thus materially exceeding the width of the somite. In the anterior 

 fragment of the type, which is 12 mm. long, the number of somites is thirty-nine, 

 in the posterior piece one hundred and thirty-five, or near that number, making 

 the total the exceptional number of one hundred and seventy-four. 



The prostomium projects forward in front of the level of the eyes as an 

 anteriorly pointed, subpyramidal process, from the sides of which project the 

 tentacles. The tentacles are proximally stout and conically pointed, the lower 

 ones attached somewhat on the ventral surface and a little farther caudad than 

 the dorsal ones, than which they are somewhat longer. The median tentacle is 

 a much more slender and shorter, distally pointed, process arising at the caudal 

 edge of a depression in front of the elevated portion of the prostomium between 

 the eyes; it projects directly forwards. Eyes large, dorsaUy elevated. (Plate 

 23, fig. 4, 5). The proboscis of the paratype is long and smooth, and bears 

 about the opening a series of pointed papillae, the precise number of which 

 could not be made out, but it is six or more. 



The fom-, or five, depending on interpretations, pairs of tentacular cirri are 

 attached one pah" on the first somite and two paks each on the two following. 

 The first tentacular cirri are cyhndiical, narrowing distad to a point, and are but 



' alatus, winged. 



