434 THE ANNELIDA POLYCHAETA. 



one. The latter is subdivided into a number of small areas by longitudinal 

 furrows which do not reach the caudal margin. Of these areas the median one 

 is most sharply defined. 



The notopodia of the seventeen setigerous somites are cylindroconical, 

 with the tips rounded. The setae are borne in a series across the tip and the 

 distal portion of the ventral surface. The setae are all slender and essentially 

 capillary, the limb being very narrow. The tip is slender and entire. (Plate 

 79, fig. 1). Excepting on the anterior somites (first six uncinigerous) the uncini 

 of the thoracic tori are arranged in a double interlocking series, those of the one 

 series progressive and of the other regressive. The uncini bear at the apex 

 one tooth above the long principal one. Toward the middle of the side toward 

 the large tooth and a little proximad of its tip is a small point or tooth. The 

 base is rounded and not at all prolonged. On the convex side is the usual 

 shoulder, which is pronounced and angular. (Plate 79, fig. 2). 



The uncinigerous tori of the abdomen are short and more or less elevated, 

 or salient. On them the uncini are arranged in a single series. The posterior 

 uncini differ conspicuously from the thoracic in that the base is much prolonged 

 in a slender acute process somewhat like those, e.g., in species of Pista. Includ- 

 ing this the uncini are considerably longer than those of the thorax. (Plate 79, 

 fig. 3). 



Locality. Panama: Perico Island. 12 March, 1891. Tlu-ee specimens, 

 two of which are broken. 



EUPOLYMNIA INSULANA, Sp. UOV.^ 



Plate 79, fig. 4-6. 



Color somewhat brown, in part of a vague greenish cast. 



The type is in two fragments, which have a combined length of 40 mm. 

 and comprise a total of sixty-six somites. At the twelfth somite the width is 

 4.2 mm. The anterior region not strongly inflated, the body narrowing but 

 moderately in going caudad. 



The prostomium forms a smooth fold bent into a semicircle open below, 

 like a conspicuous upper lip. Behind this is a narrower, transverse, incomplete 

 ring, which in other related forms bears the tentacles, three in the type of the 

 present species being all missing; the ring extends ventraUy on each side the 



' insulanus, insular. 



