176 THE ANNELIDA POLYCHAETA. 



acute. The short, composite, ventral setae are few in number. In these the 

 shaft is but shghtly curved and is gradually enlarged at the distal end. The 

 distal edge is oblique and smooth, weakly sinuous. It is finely fibrillate. 

 The shaft is finely serrate at the distal end along one side. The distal piece is 

 attached at an acute angle at one side, with the proximal edge oblique in corre- 

 spondence to that of the socket. Long, distally narrowed, and bearing two 

 small, acute and nearly equal teeth, of which the proximal is straight and the 

 distal slightly curved. Proximally, on the same side as the teeth, the edge is 

 closely finely setose. (Plate 22, fig. 4, 5). 



On the ventral side there are three stout acicula which are much stouter 

 than the setae. Each is narrowed to an acute point distally, but the tip is not 

 fine. The tips lie close together and project but very slightly from the surface. 

 A single aciculum extends into the dorsal lobe; in the distal part of its length 

 it is more slender than the ventral ones and toward the tip curves typically 

 upward. (Plate 22, fig. 6). 



Locality. Gilbert Island: off Apaiang. Surface at night, electric light. 

 Surface temp. 84° F. 3 January, 1900. One specimen. 



Aside from its exceptional breadth, this species seems to be distinguished 

 particularly by the very characteristic form of the parapodia and by the broad, 

 thin, natatory dorsal setae which are unlike any I have found described for other 

 species. The generic position of the form is very doubtful since the character 

 of any armature in the pharynx, if present, was not successfully elucidated in 

 the single type-specimen and because comparatively so few of the pelagic or 

 sexual forms in the family have been described. The presence of tentacular 

 cirri makes the position of the species in Syllis more doubtful, as the known 

 sexual forms in that genus generally lack these processes. 



Synelmis, gen. nov. 



Prostomium and peristomium distinctly separated. 



Palpi well developed, free, not at all coalesced. Eyes minute, normally 

 four pairs, those on each side in a transverse row. Tentacles very short, sub- 

 conical, smooth, and unjointed. 



One pair of tentacular cirri. 



Proboscis unarmed. 



Body long and slender. Anal cirri two, short, with no distinct median proc- 

 ess between them. 



