286 PROCEEDINGS OF THE ACADEMY OF [April, 



comprising 120 anterior segments, is 48 mm. long and has a maximum 

 width of 3.5 mm. at somite XXV. 



Prostomium (Pi. XIX, fig. 110) nearly an equilateral triangle with 

 bluntly rounded apex. A slightly elevated median dorsal field is 

 bounded b}^ a pair of shallow grooves which extend from near the apex 

 to the nuchal fold where they include nearly one-half of the prostomial 

 width between them. At these points the prostomium is attached to 

 the peristomium by a pair of folds having almost the form of ball-and- 

 socket joints, separated medially by a deep nuchal pit much wider 

 than long and covered by a nuchal fold of the peristomium. No eyes. 

 Ventral surface smooth with a deep transverse fissure just anterior to 

 the palps. Palps subquadrate cushions separated by a median furrow, 

 their lateral ends trilobate and partially united with the peristomial 

 lip behind. Immediately behind them and anterior to the lip is a 

 small fold guarding the end of the mandible. 



Peristomium and II achsetous, together not as long as the prosto- 

 mium, but much wider; I slightly longer and wider than II and thick- 

 ened below to form the lateral lobes of the lip. The anterior median 

 region of the peristomium forms a nuchal fold which roofs the nuchal 

 pit between it and the prostomium. When this is drawn back as in 

 fig. 110, the posterior or peristomial face of the pit is seen to bear a 

 vertical groove lodging a small and apparently retractile cirrus or 

 papilla, the merest tip only of which is visible when the fold is in place. 

 Anterior somites in general have the dorsum strongly arched and the 

 venter flattened. 



Except for the minute, scarcely noticeable notopodial tubercles, 

 the parapodia are imiramous. Anteriorly they are very small and 

 so near to the venter that they are scarcely visible from above. After 

 about XV they are larger and lateral, but remain nearer to the dorsal 

 than the ventral surface. They are short, thick, subcylindrical, 

 somewhat thickened at the distal end, the presetal portion of which 

 forms a hemispherical thickening. The postsetal lip is produced 

 dorso-distally into a small, erect finger-like cirrus or gill containing a 

 large vascular loop. This is fully developed on the first parapodium 

 (III) and undergoes no marked change in the first forty segments 

 (figs. Ill, 112), after w^hich it gradually diminishes in size, the thickened 

 distal end of the foot undergoing simultaneous reduction. Toward the 

 end of the piece the parapodia (fig. 113) are more slender and taper 

 to simple blunt points. 



Neuropodial acicula are three or four, stout, slightly tapered black 

 rods with colorless bases, the tips bluntly pointed and either not 



