84 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



and in the slender digitate process at the distal end of the presetal lobe. 

 Holotype. — from station 265-34 in the Allan Hancock Foundation. 

 Type locality. — Petatlan Bay, western Mexico, in 5-10 fms. 

 Distribution. — Western Mexico. 



Family Nephtyidae Grube, 1850 



The family NEPHTYIDAE Grube, as Nephthydea Grube, 1850, 

 is here recognized for 3 genera, Nephtys Cuvier, 1817, with type N. 

 hombergi Audouin and Edwards, Aglaopha?nus Kinberg, 1866, with 

 type A. lyratus Kinberg and Micronephthys Friedrich, 1939, with type 

 M. minuta (Theel). About 40 species go to the first genus, 21 to the 

 second and 4 to the third. In addition, there are 7 to 10 species too 

 poorly known to reidentify and here regarded questionable or indeter- 

 minable. The family thus comprises 65 or more species. 



In this report the 3 genera are newly interpreted. Six species, Nephtys 

 glabra, N. assignis, N. singularis, N . acrochaeta, Aglaophamus dicirris, 

 A. erectans and one subspecies, Aglaophamus rubella anops are newly 

 described. One name, Nephtys monroi, is new; two species, Nephtys 

 impressa Baird and Aglaophamus tabogensis (Monro) are revised. New 

 combinations are given in the genera A glaophamus and Micronephthys. 



The NEPHTYIDAE are partly recorded elsewhere (Hartman, 

 1940) and are not here repeated except as ranges are extended. The 

 present report concerns itself with materials that have since been de- 

 posited in the Allan Hancock Foundation of the University of Southern 

 California, together with a revision of important or type materials that 

 have been examined. 



In the NEPHTHYIDAE the body is only moderately long and 

 approximately broadly rectangular in cross section. Length (adult) 

 ranges from 10 to 300 mm; segments number 150 or fewer. The pro- 

 stomium is proportionately small, depressed and angulate, 4 to 6-sides, 

 when seen from above. There are usually 2 pairs of simple, rarely bifid, 

 prostomial antennae ; one pair is at the anteroectal margins, the other at 

 the sides of the prostomium. (Portelia Quatrefages was separated from 

 other genera for having only one pair of antennae but this has been 

 found erroneous.) Eyes are absent or present as a single pair near the 

 posterior margin of the prostomium. A pair of nuchal organs, or ever- 

 sible ciliated sacks is located at the postectal margins of the prostomium. 



The proboscis is a strong, muscular, eversible anterior part of the 

 alimentary tract. When fully extended it is cylindrical or somewhat 

 clavate. Its inner wall is armed with a pair of short, usually yellow or 



