1911.] NATURAL SCIENCES OF PHILADELPHIA. 263 



Onuphis parva sp. nov. PL XVII, figs. 51-57, and PL XVIII, figs. 98, 99. 



A small, slender species of linear form, the type measuring 36 mm. 

 long and, exclusive of the parapodia, about .6 mm. wide, with 104 

 segments. A large number of specimens are of similar size and only 

 a very few larger, the maximum being about 45 mm. long and .9 mm. 

 wide. Sexual maturity is attained at a length of 30 mm. 



Prostomium longer than usual, about one and one-quarter times as 

 long as wide, elliptical in outline. Frontal tentacles on ventro-anterior 

 border, nearly their length apart, divergent, ovate in outline with a 

 constricted pedicle, their length about two-fifths prostomium. Ante- 

 rior paired tentacles on antero-lateral border, barely reaching IV; 

 ceratophore about one-third style, 4-annulate. Posterior paired ten- 

 tacles on dorsal face close to lateral margins and slightly in advance 

 of middle, reaching IX or X; ceratophore slightly longer than those of 

 anterior pair, its basal half of three distinct rings, the distal half not 

 distinctly annulated. Median tentacle arising at almost exact center 

 of prostomium, constantly slightly shorter than posterior paired 

 tentacles, reaching only to VIII or middle of VII, its ceratophore 

 similar to that of posterior pair. Eyes situated immediately caudad 

 of base of posterior paired tentacles, usually two minute black specks 

 (sometimes coalesced into one) on each side. Palps rather prominent, 

 ovate lobes on ventral face of prostomium, projecting slightly beyond 

 its margins. 



Peristomium similar in size and proportions to immediately following- 

 segments, shortest above, where it is about one-half prostomium, the 

 latter being much more extensively exposed than in most species. 

 Nuchal cirri widely separated on extreme anterior border of peri- 

 stomium, short conical, barely reaching to middle line or posterior 

 border of peristomium. Somite II neither wider nor longer than suc- 

 ceeding segments, not embracing peristomium and its parapodia, not 

 obviously enlarged nor strongly bent forward. The first three or four 

 podous segments differ from the others only in having the walls some- 

 what firmer, the integuments more pigmented, in being more terete 

 and in having the parapodia more ventral in position. Middle and 

 posterior segments strongly depressed, with the parapodia and espe- 

 cially the gills carried high, the parapodial area thick and glandular 

 and the dorsal and ventral field flat and translucent. They are 

 remarkably uniform in size, but taper gradually in the posterior half. 



Pygidium tubular with an obliquely truncate end having a thickened 

 border and at the produced ventral margin a cluster of two pairs of 

 very slender and delicate anal cirri, the dorsal about four times as long 

 as the ventral and equal to the last seven segments. 



