1909.] NATURAL SCIENCES OF PHILADELPHIA. 347 



and usually free from it all round, scarcely wider than prostomium, 

 dorsally elevated into a convex platform-like area which in one case 

 overlaps the prostomium and partly covers the eyes. Mouth small 

 with nearly smooth posterior lip. Somites II and III similarly well 

 differentiated with similarly elevated dorsum. Tentacular cirri arising 

 from large cirrophores, the styles rather stout, tapered and short; the 

 peristomial pair about as long as prostomium and reaching to III; 

 ventral of II equal to peristomial and above its base a tubercle bearing 

 a small tuft of setae; dorsal of II about twice as long and reaching 

 VI or VII. Somite III bears a fully developed setigerous parapodium 

 and its tentacular notocirrus is equal to that of II. 



Anterior somites are uniannulate and very distinct, becoming less 

 well differentiated farther back as small interpodal annuli appear. 

 The raised dorsal field gradually merges with the general convexity of 

 the back. The venter is flat. They very gradually increase in size 

 to or beyond C, and taper thence caudad. 



Pygidium a dome-shaped ring about twice as long as the last 

 setigerous segment, bearing a pair of somewhat flattened, subcylin- 

 drical cirri resembling the posterior notocirri but rather larger than 

 they, together with a minute median cirrus (described from one speci- 

 men, station 4,431). 



Parapodia (PI. XVI, figs. 28, 29) small, little prominent and scarcely 

 exceeding one-fourth the width of their segments, but becoming 

 relatively longer and more prominent posteriorly. Setigerous neuro- 

 podia begin on II; they are slender, only slightly compressed, and 

 little tapered to a bluntly rounded presetal lip divided by a slight acicu- 

 lar notch into two equally rounded lobes, of which the subacicular is 

 usually somewhat longer; postsetal lip scarcely developed. 



Neurocirrophores broad and low, the styles (PI. XVII, figs. 28, 29) 

 subelliptical, little excavated for attachment, thick, more or less 

 foliaceous, broadest and relatively largest on anterior parapodia, where 

 they considerably exceed the neuropodia and extend somewhat beyond 

 them. Posteriorly they are relatively smaller and narrower, but often 

 so much longer that fully one-fourth of their length projects beyond 

 the neuropodia, but they always tend to diverge from the latter and 

 not to bend dorsad behind them. Notocirrophores (PI. XVI, figs. 

 28, 29) of anterior somites rather small, of middle somites low but 

 nearly as wide as the length of the neuropodia. Styles generally 

 foliaceous but comparatively small, carried nearly erect, little imbri- 

 cated and covering but a small part of the sides of the parapodia. 

 On anterior somites (fig. 28) they are regularly ovate with broadly 



