1907.] NATURAL SCIENCES OF PHILADELPHIA. 197 



blood in the anterior part and the olive-green intestine in the posterior 

 part to show through ; tentacular cirri with a red central vessel and gills 

 red throughout. 



The type and only specimen (Coll. A. N. S. P., No. 850) was dredged 

 from the soft ooze at the bottom of the deepest part of the Eel Pond 

 at Wood's Hole on August 4, 1902. Several subsequent searches have 

 failed to reveal any others. 



Prionos'pio tenuis Verrill, the only species definitely described from 

 our shores, has four minute eyes and four pairs of gills, of which the first 

 only is branched, the others being foliaceous. A larger specimen, 

 probably representing a distinct species, is recorded as having all of 

 the 4( ?) pairs of branchiae lanceolate and pectinate posteriorly, with 

 slender papillse. Webster and Benedict record an undetermined 

 species at Provincetown, Massachusetts. The four or five European 

 species are all easily distinguished by the characters of the prostomium, 

 gills and crochets. 



Numerous species of Polydora have been described from both sides of 

 the Atlantic. Eight species occur in the region about Wood's Hole, 

 the following two of which are new^ and rather closely related. 

 Polydora anoculata sp. nov. 



Form very slender and elongated, anterior half depressed and of 

 nearly uniform width; posterior half gently tapered, nearly terete. 

 Length up to 20 mm., breadth at VI 35 mm. Number of segments 

 about 98. 



Prostomium (Plate XV, figs. 7, 8 and 9) about 3 or 4 times as long as 

 broad, not prolonged caudally beyond somite II, but truncate or 

 broadly rounded ; anterior half abruptly bent downward, with a steep 

 front; sides straight or slightly concave in anterior half; anterior end 

 cleft medially, the halves diverging as a pah- of rather prominent, 

 short, rounded lobes, which may be drawn together or separated. 

 Eyes totally absent and no nuchal ridge nor nuchal cirrus. 



Peristomium (figs. 7, 8 and 9) bounding mouth by a small simple 

 posterior lip ; lateral cephalic lobes nearly meeting below, compressing 

 the ventral portion of prostomium between them and extending as 

 far forward as the base of anterior prostomial lobes. Tentacular 

 cirri arising from posterior dorsal region of peristomium, in contact 

 with sides of prostomium, rather stout, length three or four times width 

 of body, reaching to XIII or XV, constricted at base, then widened, 

 then tapered to blunt tip, channeled for entu-e length, and much 

 wrinkled transversely. 



Segments all well marked, uniannulate, those of the anterior ^ 

 14 



