Vou.2]  Ksterly—Copepoda of the San Diego Region. Bul 
both are uniramous. The left 4-jointed, the right 1- to 4- jomted 
or lacking. Head appendages of male retrograded and modified, 
body shortened. 
KEY TO SPECIES. 
AN GON Will 8) OR Zh TSGUNTMIS. coco cobs asadococens0e000g500e g 
AN KOON Yanda (3) CeAMIEMISs bo a ooe conc cor oud ecooUnBU OD REDO ODOC 4 
91. Two segments between anal and genital segments (fig. 6a)...... 
Jo sb ow eco dub noamomtinn Cmome bod Gd 6 ning. Go-cto molec E. elongatus 
1. One segment between genital and anal segments (fig. 7b)....... 2 
2. Inner border of second basal of mandible divided into two 
approximately equal portions by the insertion of the inner 
rep (Cie WO) soasasaccdescosouogeocecHodqon yon E. attenuatus 
Ze eroximalsporiion: much) lono er thangs taller pottetspeneltalcieleNelensl-i-r1 3 
3. Two terminal bristles of left side of furca longer but hardly 
thicker than on the right side; genital segment (fig. 8d) much 
broader hans lone oniton-shia Peds eis itt ello sell lelelct en E. crassus 
3. Two terminal bristles of left side of furca longer and much 
thicker than on the right side. Second basal of maxilla with 
four inner marginal bristles; forehead (fig. 9a) triangular, 
TROMUACNG! I IMO, Gosoopoaueade mss ugecgooSonoDoUDbE E. subtenuis 
$1. Both feet of fifth pair present ..........-.- 2. sees eee e ee eee eee 2 
Ie Rireht foot of dikth pair aWSeMba ca. <a oc we lem seems lene mea 3 
2. Outer ramus of posterior antenna does not extend by far to the 
distal border of the first joint of the outer ramus..... E. elongatus 
2. Outer ramus reaches almost to the distal border of first joint of 
IMAG 5 ocogdousscooesas boobn Ub Gobo Um UOGooD ODOR Gar EB. attenuatus 
3. Terminal joint of fifth foot at least as long as the apical bristle; 
outer border of second joint of inner ramus of second to 
fourth (as in fig. 8a) feet without tooth................ E. crassus 
3. Terminal joint of fifth foot shorter than apical bristle. ..E. subtenuis 
1. Eucalanus elongatus Dana. 
Calanus clongatus Dana, 1848, p. 18; 1849, p. 278; 1852, p. 1079; 
1855, pl. 75, figs. la, b. 
Eucalanus elongatus Giesbrecht, 1892, pp. 131, 149, pl. 11, figs. 
2, 7, 12, 20, 25, 32, 36; 1895, p. 246; 1898, p. 20. 
2 Two free segments between genital and anal, former 
longer than broad ( fig. 6a, 6). Forehead of regular triangular 
shape. First and second joints of outer ramus of posterior anten- 
nae not fused, first joint of inner ramus little longer than the 
second and over three times as long as broad. Inner margin of 
second basal of mandible with three bristles. End of inner ramus 
does not reach distal end of second basal by about the length of 
the ramus; its first joint with 2, the second with 5 bristles. See- 
