4 
(od) 
Vou.2] Hsterly—Copepoda of the San Diego Region. 1 
of posterior antennae about equal in length, outer ramus with 
seven joints. Blade of mandible with few but strong teeth. Sec- 
ond basal joint of the posterior maxilliped at least three times 
as long as the inner ramus of five joints. Inner marginal bristle 
of first basal of the swimming feet long and richly plumose, 
terminal bristle of outer rami finely toothed; fifth pair absent. 
4 Head fused with thorax; abdomen with five segments, ana! 
segment short; innermost bristle of furea shortened and bent at 
an angle. Blade of mandible, appendage of inner border of max- 
illa, and anterior maxilliped stunted ; less obvious differences also 
in the posterior antennae and maxillipeds and swimming feet ; 
outer ramus of first pair of feet 3-jointed. Feet of fifth pair 
long, strongly built, and of rather complicated structure (fig. 
23a). 
KEY TO SPECIES. 
J Earlre(ol ne SOO RMEET OFS (CNN acto oer Cre MeC LG Ole o Abin ae Sie Gi OCIS AiO ean fe) 
JRA EGINE MHOYONE. OREN Ne ers-oetaln eae So ooo oid a ebitoe od colds ie OImeini eco 4 
41. Terminal joint at each foot of fifth pair, with long straight or 
slightly curved stylet; elevation for frontal organ not pro- 
TIRUNGHB IED” 5% Gi oa ed cele haw BU CIO oo GOO OOmorn SLAG pion oro bane E. acuta 
91. Hairs of frontal organ on a low elevation (fig. 25b)............. 2 
1. Hairs of frontal organ on an elevation which extends toward the 
fer OMityp (UO LAD) cre tataye srevekete cick sie leks iene NsFo: eres oie 6] 4) let Cxaiyn siaeve ts o/s 4 
2. Genital segment with asymmetrical outgrowths (figs. 25c, d); no 
bristle in middle of outer border of first joint of outer ramus 
of the first foot; terminal bristles of furca about equal in 
length, the dorsal (inner) bristle much longer and thicker 
Giles; BH) scpesgcanoodotonssaadgpqoornonebootegueseucnaune 3 
3. Genital segment with a knob-like protuberance in front on the 
IGE BIC Gee cdcos at docls pbodsoD oud Gonos Con ocomopnednaT BE. acuta 
3. Genital segment without such an outgrowth ............... E. media 
4. Middle spine on outer border of terminal joint of second foot 
longer than the others, and the distal indentation in the border 
GReey asin (CUE MEU KO coe ec clan CIpIAeicO On Olceced Ok minInImicacieRcrO e Cria 5 
SAnterionantennaesloneer tham boOdiye sc aces see E. spinosa 
Or 
1. Euchaeta acuta Giesbrecht. 
Euchaeta acuta Giesbrecht, 1892, pp. 246, 262, pl. 16, figs. 6, 10, 
14, 18, 21, 27, 39 ;pl. 37, figs. 47, 48, 52; 1898, p. 38. 
2 Elevation on front of head flat; genital segment asymmet- 
rical, more strongly convex on the right side than on the left, 
and with more prominent process at the right of the opening; a 
knob-shaped outgrowth on anterior part on left side. Furea 
