340 PROCEEDINGS OF THE ACADEMY OF [June, 



been recently regenerated — being abruptly unpigmented and of smaller 

 size. 



Form slender, depressed, the segments scarcely exceeding one-third 

 of total width between margins of notocirri or tips of parapodia. 

 From the maximum width at the end of the anterior fourth the extreme 

 outline tapers slightly forward and regularly and continuously caudad. 

 Length 44 mm.; maximum width of segments 1.6 mm.; total width 

 3.8 mm. Segments 88. 



Prostomium very short, broad and depressed, decidedly bent down- 

 ward. In the figure (PI. XVI, fig. 19) the prostomium is represented 

 as pressed upward somewhat, but in the position in which it naturally 

 rests the anterior outline is regularly semicircular and the length 

 (exclusive of the posterior prolongation) about one-half the width. 

 From the slightly convex posterior margin a median prolongation fits 

 into a deep depression in the peristomium and bears a knob-like nuchal 

 cirrus having a diameter about equal to the eyes. Eyes one pair, con- 

 spicuous, circular, brown, about one-ninth or one-eighth the width of 

 the prostomium and widely separated by an interval of about five 

 times their diameter, close to the posterior margin of the prostomium. 

 Frontal tentacles very short, subcorneal with small terminal append- 

 ages, very widely separated and somewhat reflexed on sides of prosto- 

 mium ; the dorsal about as long as one-third width of prostomium and 

 separated by about twice their length; the ventral somewhat longer, 

 nearer together and reflexed so that they are concealed in dorsal views. 



Peristomium somewhat tumid laterally, but excavated dorso-medially 

 for the nuchal projection and papilla, almost indistinguishably 

 coalesced with II which is similarly tumid laterally but lacks a median 

 depression. 



Tentacular cirri four pairs, rather short, thick, blunt, and stiff. 

 The first (or peristomial) pair scarcely longer than width of prostomium 

 and not reaching beyond IV; dorsal of II with a much larger cerato- 

 phore and reaching VII ; ventral of II equal to peristomial and that 

 of III (notocirrus) similar to dorsal of II and reaching VIII. 



Podous segments well defined, very regular, the anterior very short, 

 but soon becoming one-third as long as wide, slightly convex above, 

 flat below, with a shallow neural groove. Posteriorly the segments 

 taper to a very minute pygidium bearing a pair of relatively stout, 

 cylindroid anal cirri, the combined width of which equals that of the 

 pygidium and the length the last five or six segments. 



Parapodia (PL XVI, fig. 20) begin on III, strictly lateral, prominent, 

 their length exceeding one-half width of body, toward the ends becom- 



