The adult male can be recognized easily by 

 the characteristic fifth pair of legs, which has 

 a strong spine on the internal margin of the 

 first segment of the right exopod. The fifth 

 copepodid male is distinguished by the man- 

 dible, which, like that of the adult female, has 

 a strong spine on the basis. 



Euchirella rostrata Claus, 1866 



Occurrence 



Sta. 5. 12 adult females, 3.26 to 3.45 mm. 

 Sta. 7. 22 adult females, 3.36 to 3.64 mm. ; 



1 adult male, 2.97 mm. 

 Sta. 9. 17 adult females, 3.36 to 3.74 mm.; 



1 adult male, 3.00 mm. 



Sta. 13. 3 adult females, 3.60 to 3.80 mm. 

 Sta. 15. 6 adult females, 3.80 to 4.00 mm. 



Remarks 



This species is one of the most common in 

 the present collections, but the male is rare. 



Undeuchaeta plumosa Lubbock, 1856 

 Occurrence 



Sta. 5. 4 adult females, 3.74 to 3.93 mm. 

 Sta. 9. 5 adult females, 3.84 to 4.12 mm. ; 



2 adult males, 3.55 to 3.72 mm. 



Remarks 



The present specimens are in full agreement 

 with the figures given by Grice (1962). 



FAMILY EUCHAETIDAE 



Euchaeta manna (Prestandrea, 1833) 



Occurrence 



Sta. 3. 1 fifth copepodid female, 2.90 

 mm. ; 



3 adult males, 3.60 to 3.74 mm. 

 Sta. 5. 1 adult female, 3.55 mm. 



Remarks 



According to Grice (1962), this species is 

 fairly common in the equatorial Pacific Ocean, 

 but it seems to be rare in the central North 

 Pacific. 



Euchaeta spinosa Giesbrecht, 1892 

 (Plate 7, figs. 12-15) 



Occurrence 



Sta. 3. 5 adult females, 6.24 to 6.43 mm. ; 

 1 adult male, 6.24 mm. 



Sta. 5. 13 adult females, 6.33 to 6.91 mm. ; 



7 adult males, 5.97 to 6.24 mm. 

 Sta. 7. 3 adult females, 6.33 to 6.72 mm. ; 



1 adult male, 6.33 mm. 

 Sta. 9. 2 adult females, 6.33 mm.; 



4 adult males, 6.14 to 6.52 mm. 

 Sta. 13. 3 adult females, 6.81 to 7.20 mm. 



Remarks 



The female of this species can easily be 

 recognized by the high frontal prominence of 

 the head, the slender rostrum, and the asym- 

 metrical genital segment. 



The male has a very slender body with a 

 triangularly produced forehead (fig. 12). The 

 right fifth leg (fig. 13) has a 2-segmented 

 exopod and a 1-segmented endopod; the endo- 

 pod is as long as the first segment of the 

 exopod. The left fifth leg has a 3-segmented 

 exopod and a small rudimental endopod. The 

 second exopodal segment has distally a pro- 

 jection which is as long as the segment itself 

 and which has a row of acute, triangular teeth 

 along the margin (figs. 14 and 15). 



Euchaeta media Giesbrecht, 1888 

 (Plate 7, figs. 16-22) 



Occurrence 



Sta. 5. 2 adult females, 4.03 to 4.12 mm. 

 Sta. 9. 11 adult females, 4.22 to 4.51 mm.; 



5 adult males, 3.79 to 4.03 mm. 

 Sta. 13. 1 adult female, 4.51 mm. 



The female (figs. 16-18) is well character- 

 ized by the shape of the genital segment, but 

 the description of the male is rather incom- 

 plete (Wilson, 1950). The following description 

 was made from the specimens from station 9. 



Description of Male 



The total length ranges from 3.79 to 4.03 mm. 

 The proportional lengths of the prosome and 

 urosome are 2.2:1. The forehead in dorsal as- 

 pect is produced triangularly, but in lateral 

 view is smoothly rounded into a slender rostrum 

 that is curved slightly downward (fig. 19). 

 The antennule is 23-segmented and reaches to 

 about the distal end of the metasome. 



The right fifth leg (fig. 20) consists of a 

 stout basipod, a 2-segmented exopod, and a 

 1-segmented endopod. The endopod is shaped 

 like a ladle and is equal in length to the proxi- 



CALANOID COPEPODS FROM NORTH PACIFIC 



551 



