The 24-segmented antennule (plate 6, figs. 

 17 and 20) reaches the end of the second 

 urosomal segment when applied against the 

 body. Articulations between the 8th and 9th, 

 the 11th and 12th, and the 23d and 24th seg- 

 ments are incomplete. 



In the antenna (plate 6, fig. 21), the endopod 

 is much better developed than in the female, 

 reaching about two-thirds the length of the 

 exopod. The basipod and the first endopodal 

 segment, however, are devoid of setae. 



The mouth parts are all reduced. The mandi- 

 ble (plate 7, fig. 1) lacks the mandibular blade. 

 In the maxillule (plate 7, fig. 2), the first inner 

 lobe is reduced to a mere round process that 

 lacks .setae or spines, and the second and third 

 inner lobes are absent. The basis has no setae. 

 The endopod is small, with 5 setae, but the 

 exopod is much better developed than in the 

 female and has 10 large setae plus 1 small seta. 



In the maxilla (plate 7, fig. 3), the first to 

 fourth lobes lack setae or spines. The fifth 

 lobe has 2 setae. The endopod is 2-segmented 

 and has 1 seta on the first and 4 setae on the 

 second segment. In addition, there is a seta 

 at the insertion of the endopod. The coxa of 

 the maxilliped (plate 7, fig. 4) has a single seta 

 and some scattered spinules on the distal lobe. 



The legs of the male differ from those of 

 the female in certain respects. In the first leg 

 (plate 7, fig. 5), the first exopodal segment 

 lacks external spines. The endopod of the sec- 

 ond leg (plate 7, fig. 6) is a single segment 

 without a visible line of fusion. The fourth 

 leg (plate 7, fig. 8) lacks coxal spines and 

 closely resembles the third (plate 7, fig. 7), but 

 diff"ers from the same leg of the female. 



The fifth pair of legs (plate 7, fig. 9) con- 

 sists of a uniramose left leg and a well-devel- 

 oped, biramose right leg. The left leg has 5 seg- 

 ments. The small distal segment is inserted a 

 short di.stance proximal to the end of the 

 preceding segment; the 2 segments together 

 thus form a minute chela. The di.stal segment 

 carries 2 teeth apically. The external tooth, 

 which is the larger, curves outward, the in- 

 ternal one inward (plate 7, figs. 10 and 11). 

 The right leg consists of a 2-segmented basipod, 

 a 1-segmented endopod, and a 2-segmented 

 exopod. The basipod is well developed, reaching 

 the middle of the third segment of the left leg. 



The endopod is S-shaped, and has a triangular 

 prominence along the external margin, one- 

 third the length from the proximal end. The 

 first exopodal segment has 2 prominences along 

 the proximal one-third of the internal margin ; 

 the distal one of these is much larger than the 

 other. The distal segment is S-.shaped and has 

 a row of small teeth along the internal margin. 



Remarks 



This species is closely related to K. truncata, 

 but the female can easily be distinguished from 

 that of the latter by her smaller size and the 

 shape of the genital segment. The male of this 

 species is characterized by the shapes of the 

 teeth on the terminal segment of the left fifth 

 leg and by the arrangement of the prominences 

 on the exopod and endopod of the right fifth 

 leg. 



Type material of f^. iinispina from station 5 

 has been deposited in the U.S. National Museum 

 as follows: Holotype female (USNM 113238) ; 

 allotype male (USNM 113239) ; six females as 

 paratypes (USNM 113240). 



Euchirella amoena Giesbrecht, 1888 



Occurrence 



Sta. 3. 1 adult female, 3.84 mm.; 



1 adult male, 3.20 mm.; 



3 fifth copepodid females, 2.89 to 

 3.07 mm.; 



4 fifth copepodid males, 3.00 to 

 3.09 mm. 



Sta. 5. 2 adult females, 3.74 to 3.84 mm. ; 

 3 adult males, 3.45 to 3.55 mm.; 



2 fifth copepodid males, 3.26 mm. 

 Sta. 7. 1 fifth copepodid female, 3.13 



mm. ; 

 1 fifth copepodid male, 3.16 mm. 

 Sta. 9. 1 fifth copepodid female, 3.00 mm. 



Remarks 



The male of this species had been known as 

 E. amoena and the female as E. brevis, until 

 Grice (1962) synonymized them. 



The female is well characterized by the .stout, 

 almost globose body, the last metasomal seg- 

 ment (with a pointed ridge on its posterolateral 

 margin), and by the presence of 4 small acute 

 teeth near the base of the internal seta of the 

 coxa of the fourth leg. 



550 



U.S. FISH AND WILDLIFE SERVICE 



