98 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Setae are of 2 kinds including preacicular barred, and postacicular 

 lanceolate ones. The barred ones were originally described as "minutely 

 joined." The joints are presumed to have referred to the transverse 

 bars, and not an articulation. Postacicular setae are long and blade-like, 

 the outer edge delicately serrated with transverse series of spinelets. 

 These setae are easily broken and obliquely slivered ; many therefore, 

 are broken off or remain as shattered stumps. No furcate setae have been 

 identified. Baird described a third kind of setae as "compound, the 

 edges of the appendage toothed as is also the top of the shaft." I am 

 unable to find such setae or to account for the presence of compound 

 setae in any member of the family NEPHTYIDAE; the reference 

 may have been to the broken, partly splintered postacicular setae. 



N. impressa is characterized for having superior lobes in neuropodia 

 present in anterior and posterior segments; interramal cirri are first 

 present from segment 4. The subdistal papillae of the proboscis are in 

 only 4 or 5 rows. 



Distribution. — N. impressa is known only from Patagonia, southern 

 South America. 



Nephtys singularis, new species 

 Plate 15, figs. 1-6 



Collections.— 495-36 (1+) ; 770-38 (1 + ) ; 930-39 (2—). 



This is a slender, prolonged species. One specimen not quite com- 

 plete and with proboscis retracted, measures 33 mm long for 102 seg- 

 ments; greatest width is 1.8 mm at about the fifteenth segment. There 

 is no pigment except on the prostomium where the dorsal surface is 

 slightly diffused with dark color. The species is otherwise conspicuous 

 for the greatly prolonged neuropodial postsetal lobes through median 

 and posterior segments, causing the specimen to appear ragged. 



The prostomium seen from above is approximately rectangular (pro- 

 boscis retracted) and longer than wide; the 4 frontal antennae are 

 subequal, with the ventroposterior pair the larger; all are simple and 

 taper distally. Nuchal organs at the postectal margins are visible as 

 papillae (fig. 1). 



The proboscis when everted is clavate in shape; it terminates dis- 

 tally in 22 bifurcated papillae as typical of other species; the same 

 number of rows is continued in the subdistal series. These are largest 

 at the forward (everted) end and number to 7 or 8 in a longitudinal 

 series; they diminish in size gradually going back. The proximal sur- 

 face is smooth but may appear somewhat wrinkled when the proboscis 

 is not fully everted. There is no distinct middorsal or midventral larger 

 papilla. 



