114 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 25 



Genus Raricirrus, new genus 

 Type R. maculata, new species 



The prostomium is a simple, semicircular lobe followed by two buccal 

 segments lacking parapodia. The following 9 segments have biramous 

 parapodia and paired lateral branchiae. The next 3 segments are without 

 branchiae. Segment 13 has a pair of short processes (possibly elongated 

 nephridia), followed by 10 or more segments without lateral branchiae. 

 The body terminates in a simple pygidium with dorsal anal pore. 



All parapodia are biramous and each is represented by a low papilla 

 provided with simple setae. Notopodial setae are entirely slender and 

 capillary ; neuropodial setae are falcigerous. This genus differs from 

 other genera of the family in lacking paired palpi and dorsal tentacles ; 

 branchiae are limited to a few pairs on median segments. 



Raricirrus maculata, new species 

 Plate 21, figs. 1-3. 



Collections. VELERO IV Sta. 5027, 1.9 mi from Point Fermin 

 light, California, in 38 fms, medium green black silty sand (6). Sta. 

 5096, 2.5 mi from same place, in 25 fms, same kind of sediment (51 ). 



The body is flesh colored and has dark pigment in an irregular 

 pattern. Total length is 7 to 10 mm; setigerous segments number about 

 22. The prostomium is a small, simple lobe without eyes but with a 

 pair of nuchal slits, best seen in lateral view. The next 2 segments are 

 slightly longer and comprise the buccal region. The following 9 segments 

 are cylindrical, have paired biramous parapodia with short to long (PL 

 21, fig. 1) lateral branchiae. Segments 10 to 12 are larger and broader, 

 characterized by containing ovigerous products and covered with a thin 

 epithelium. The thirteenth segments has a pair of short cirri (perhaps 

 nephridial) originating behind the notopodial papilla. This segment is 

 followed by a broadly depressed posterior tail with segments much 

 broader than long, and the posterior end terminates in a small triangular 

 pygidium with dorsal anal pore. 



Lateral branchiae vary considerably in length ; at their greatest de- 

 velopment they are as long as the body and marked with dark pigment 

 patches in irregular arrangement. Preserved, they are wrinkled as though 

 capable of considerable extension. On some individuals they are much 

 shorter, reduced to mere stubs, suggesting that they may be regenerated. 

 They originate immediately behind the notopodial lobe or slightly above 

 it, and near the posterior half of the segment. 



