IL^THAGUS ASCENDENS. 403 



are short and strongly marked; as usual, they become proportionately longer 

 distad, though the absolute increase is not gi'eat and the relative increase not 

 so great as frequent in species of related genera. (Plate 69, fig. 7-9). The 

 dorsal setae have a similar structure, but are very much finer, with the annuli 

 commonly longer. (Plate 69, fig. 4-6). The specimens give no evidence of the 

 longer special setae such as form a head-cage in most genera. 



Locality. OfT Mexico: Sta. 3415 (lat. 14° 46' N., long. 98° 40' W.). 

 Depth 1,879 fms. Bottom of green mud and Globigerina ooze. 10 April, 1891. 

 Three specimens. 



Ilyphagus PLUTO, sp. nov. 



This is a smaller and notably more slender species than the preceding, 

 subcylindrical, moderately narrowed cephalad, the anterior end a Uttle obUquely 

 truncate, while at the posterior end the body is abruptly narrowed so as to present 

 a short, much narrower, caudal region. 



Surface covered with filaments as in the preceding species, but these less 

 dense and rather coarser proportionately. Adhering to this coat was much 

 foreign material, including, e.g., shells of Foraminifera. 



Around the margin of the truncate anterior end, which has a diameter of 

 8 mm., is a series of twenty stout, cylindrical processes distally divided into 

 short rounded lobes, these being apparently retracted branchiae; the processes 

 are laterally contiguous and form a completely closed circle. 



Whereas in bythincola the coarse ventral setae are pale straw colored 

 throughout, in the present species they are much darker, reddish brown or 

 sorrel-colored, excepting the extreme tips, which are pale. They are long and 

 stout and terete, excepting at the tips, where they are flattened and moderately 

 curved, with acute apex. In middle region of body, 19 mm. long. Notopodials 

 also red-colored; smaller than the neuropodials, but much coarser in proportion 

 than in bythincola. Setae of anterior region lost. 



Length, 42 mm.; width, 11.5 mm. 



Locality. Off Peru: 88 m. S. W. of Palominos Light House. Sta. 4672 

 (lat. 13° 11' 30" S., long., 78° 18' W.). Depth 2,845 fms. Bottom of fine dark 

 green mud. Bottom temp. 35.1° F. 21 November, 1904. 



Ilyphagus ascendens, sp. nov. 



In general appearance much more resembling bythincola than the preceding 

 species. The type is a little longer than those of abyssicola and is more uniform 



