Vou.2]  Esterly—Copepoda of the San Diego Region. 147 
Occurrence: San Diego, May 31, 1904, eight females; two 
males which seem to be of this species were taken also’ at this 
time, but they are distinctly immature. 
3. Genus Undeuchaeta Giesbrecht. 
Euchaeta (in part) Brady, 1883, p. 57. 
Undeuchaeta Giesbrecht, 1888, p. 335; 1892, pp. 54, 227, 766; 
1898, p. 33. 
Undeuchaeta Sars, 1900, p. 58, pls. 15, 16. 
Undeuchaeta Wolfenden, 1903, p. 267. 
2 Abdomen with four segments, the first with the genital open- 
ing on the convex ventral surface, at least as long as the second 
and longer than the last segment. Lateral angles of last thoracic 
segment rounded, or at least not produced into spines. Anterior 
antennae 23-jointed, outer ramus of first foot 2-joimted, inner 
ramus l-jointed. Outer ramus of posterior antennae at least 114 
times as long as the inner; outer ramus of maxilla (fig. 16e) 
small, middle bristles shorter than the distal and proximal ones, 
outer marginal lobe with much elongated middle bristles. 
4 Anterior antennae 21-jointed, cephalo-thorax with four 
segments, abdomen with five, anal segment very short. Head with 
rather high crest (fig. 16d), last thoracic segment prolonged into 
angles, but not pointed. Inner ramus of posterior antennae 34 
as long as the outer. Mandible, maxilla and maxillipeds much 
reduced. Outer ramus of first foot indistinctly 3-jointed. 
Left foot of fifth pair uniramous (inner ramus reduced 
to a very small, rod-like projection), outer ramus (fig. 16f) end- 
ing in a short style (terminal joint of ramus). Right foot bira- 
mous. Terminal joint of outer ramus produced into a long 
stylet, inner ramus as in Euchaeta (cf. fig. 23a) ; outer ramus of 
each foot 3-jointed. The second joint of the outer ramus of the 
left foot (fig. 16f. Re. 2) bears a toothed process (fused with the 
joint) which flares distally ; at the base of this and on the second 
joint is articulated a process, which together with the terminal 
joint of the ramus and the toothed process forms a forceps. 
The abdominal segments are densely covered with fine spines 
or hairs, and the posterior margins of the segments are toothed. 
In the structure of the fifth pair of feet these male animals 
very closely resemble the males of the genus Huchaeta, but seem 
