Vou.2] Hsterly—Copepoda of the San Diego Region. 133 
2. Eucalanus attenuatus Dana. 
Eucalanus attenuatus Dana, 1848, p. 18; 1849, p. 278; 1852, p. 
1080; 1855, pl. 75, figs. 2a-e. 
Calanus mirabilis Lubbock, 1856, p. 16, pl. 5, figs. 1-6. 
Calanella mediterranea Claus, 1863, p. 176, pl. 28, figs. 6-11. 
Eucalanus attenuatus Giesbrecht, 1892, pp. 131, 150, pl. 3, fig. 1; 
pl. 11, figs. 1, 11, 13, 16, 18, 24, 40; pl. 35, figs. 3, 6, 17, 
25, 34, 37; 1898, p. 20. 
fta.seg. ri. 
Fig. 7.—Eucalanus attenuatus. (a) Head of female, dorsal, X20. (0) 
Abdomen of female, X31. Gen. seg., genital segment. F.-+-a. 
seg., furca and anal segment. (¢) Mandibular rami, female, 
x31. Ri., inner ramus. 
Q Forehead (fig. 7a) triangular, indented on each side, much 
tapering. Genital segment longer than broad, between it and 
anal segment but one free segment (fig. 76). First joint of inner 
ramus of posterior antenna 4 times as long as broad and 114 
times as long as the second; two inner marginal bristles on second 
basal of mandible (fig. 7c), end of inner ramus distant from 
distal end of second basal more than the length of the ramus. 
Maxilla as in EZ. elongatus; first joint of inner ramus of posterior 
maxilliped with 3 bristles, second with four. 
4 Pronounced secondary sexual characters; right fifth foot 
present, left considerably shorter than the fourth foot. 
Coloration : Similar to that of HL. elongatus; 1 have never seen 
animals with the plumes at the ends of the antennae entire; in 
Wheeler’s specimens they were colorless; in Giesbrecht’s at 
times orange and iridescent. 
Length: Female, from 4 to less than 5 mm.; male, under 3.5 
mm. 
Occurrence: A few come in the hauls with elongatus, but are 
not nearly so common. They were especially abundant in June 
and July, 1903. 
