296 



PROCEEDINGS OF THE ACADEMY OF 



[Mch., 



smooth and exhibits httle of the nodular character seen in some species. 

 The median tentacle has a total length slightly exceeding the prosto- 

 miiim, of which about one-fourth or more constitutes the strongly 

 clavate basal piece. The style is slender and regularly tapering, and 

 in no case exhibits any trace of the club-shaped extremity figured by 

 Mcintosh for A. aculeata. The palpi are from six to eight times as long 

 as the prostomium and nearly twice as long as the first parapodium 

 and tentacular cirri; in form they are slender and regularly tapering. 

 Nothing peculiar appears in the form or modifications of the para- 

 podia, ^^•hieh resemble those of A. aculeata, though the first pair appear 



to be rather longer, their tips reaching about 

 1^ times the length of the prostomium beyond 

 the latter. The ventral cirri reach to the 

 middle roAv of neuropodial setae, while the 

 dorsal cirri extend fully one-third of their 

 length beyond the tips of the longest of the 

 latter, being therefore relatively somewhat 

 longer than in A. aculeata. 



The general arrangement of the several 

 forms of setse is that usual in the genus. Of 

 the three series of neuropodials the dorsal 

 invariably contains two, the middle usually 4, 

 and the ventral 8, though 5 may occasionally 

 occur in the middle and 7 to 8 in the ventral 

 series. All of these setae are brown and de- 

 cidedly iridescent, and the slender ones ciuite 

 pale. In the dorsal row both spines (fig. 1) 

 are ^■ery stout, and both terminate in blunt 

 points which probably result from wear, 

 though not a single one of these spines in any 

 of my specimens presented a I'eally acute 

 tip. The middle setae (fig. 2) arc moderately 

 and the ventral (fig. 3) decidedly slender, and 

 both arc similarly formed, with acute attenu- 

 ated tips not preceded l^y any enlargement 

 and not concealed in a pilose coat, though those newly extruded are 

 sheathed. In the dorsal series the anterior seta is frequently stouter, 

 while those in the other two increase in size from before backward. 

 Toward the caudal end, coincidentally with the reduction in size of 

 the parapodia, these setae become more slender, smaller and fewer, 

 and on the last 7 or 8 parapodia are altogether wanting. 



Figs. 1, 2 and 3. — Neu- 

 ropodial seta? from somite 

 X. Anterior of dorsal, 

 posterior of middle, and 

 middle of ventral series, 

 respectively. All X 56. 



