1910.] - NATURAL SCIEN'CES OF PHILADELPHIA. 359 



region little more than one-third from the posterior end where the 

 sides swell out abruptly and promhiently; from this point the sides 

 are nearly straight and converge rapidly to the anterior lobes which 

 are small and separated by a wide fissure occupied l)y the l)a.-,e of the 

 median tentacular ceratophore; cephalic peaks minute, well separated 

 from the median ceratophore and well above and free from the lateral 

 tentacles. Dorsum of prostomium very smooth, prominently elevated 

 posteriorly and sloping regularly to the peaks; median fm-row very 

 slightly developed and no trace whatever of pigmented eyes. 



Median tentacle (Pi. XXX, fig. 34) with large ceratophore nearly or 

 quite one-half the length of the prostomium and rapidly tapered from 

 the broad base which is inserted for only a short distance into the 

 prostomium and united to its anterior lobes. Style slender, delicate, 

 flagelliform and regularly tapered to the end; scarcely twice length of 

 prostomium. Lateral tentacles arising from small, slightly tumid 

 ceratophores beneath peaks and at a level lower than the median 

 ceratophore; the styles small, about as long as median ceratophore, 

 subulate, tapering to slender tips. Palps slender and elongated, 

 nearly twice median tentacle, regularly tapered, smooth, terete, 

 longitudinally striated and terminated by a minute filament. Facial 

 ridge prominent, reaching to trifid mouth which ls bounded by rugous 

 lips. All cephalic appendages thickly clothed with minute sensory 

 cilia which on the i)alpi are scarcely elevated above the surface. 



Peristomium obsolete except laterally where it is crowded far 

 forward in the form of parapodia bearing the tentacular cirrophores, 

 which reach the level of the prostomial peaks, and a small achaetous 

 acicular lobe. Styles of tentacular cirri resembling median tentacle, 

 smooth, slender, tapered, and lackmg subterminal enlargements, the 

 dorsal about equalling, the ventral three-fourths as long as the median 

 tentacle. Body rather narrow and depressed, regularly tapered from 

 near the anterior end; below with prominent lateral muscular ridges 

 bounding a furrow in which is a prominent neural ridge. On the 

 dorsum each segment is marked with deep transverse depressions. 

 Nephridial papillae begin on VI, arising from the sides of small eleva- 

 tion-; in the usual position; they soon become long tubes curved 

 upward and backward into the interpodal furrows. Pygidium un- 

 known. 



Parapodia (PI. XX.\. fiu;. 35) very prominent, on anterior segments 

 quite equal to width of body, posteriorly still longer, projecting 

 strictly laterad, the l)ase broad and compressed, the rami well-difTer- 

 entiated. X'otopodia ratlicr prominent projections from the strongly 



