150 University of California Publications. | ZooLogy 
2 Head without crest (fig. 17a), genital segment with a spine 
on the dorsal surface. 
Coloration: Similar to that of U. major. The digestive tract 
of the single specimen was filled with orange red material. 
Length: Female, 3.18 mm. 
Occurrence: San Diego, June 14, 1904. 
4. Genus Euchirella Giesbrecht. 
Undina (in part) Lubbock, 1856, p. 21. 
Calanus (in part) Lubbock, 1856, p. 15. 
Undina Claus 1863, p. 186. 
Euchaeta (in part) Brady, 1883, p. 59. 
Euchirella Giesbrecht, 1888, p. 336; 1892, pp. 54, 233, 743; 1898, 
p- 34. 
Euchirella Cleve, 1900, p. 4. 
Euchirella Wolfenden, 1903, p. 267. 
Rostrum present in most species, simple; lateral angles of 
last thoracic segment not pointed. Inner ramus of posterior 
antennae 14 to 14 as long as the outer ramus, the two proximal 
‘ joints of which are fused. Inner and outer rami of the maxilla 
short, the former provided with heavy hooked bristles. Outer 
ramus of the first pair of feet 2-jointed, that of the second to 
fourth pairs 3-jointed. Inner ramus of first and second pairs 
1-jointed, of the third and fourth 3-jointed. Right foot of fifth 
pair of male with shear-like formation of distal portion, the left 
foot stylet-like (ef. figs. 18d, 19d). 
2 Head not always distinct from thorax, last two thoracic 
segments fused., Abdomen with four segments, genital segment 
and fureal bristles symmetrical or asymmetrical. Anterior an- 
tennae with 23 joints, reaching to the end of the thorax or some- 
what beyond. Second basal of posterior maxillipeds twice as 
jong as the 5-jointed inner ramus. Feathering on the inner 
margin of the proximal basal joint of the fourth pair of feet 
replaced by spines. Fifth pair of feet absent. 
& Head oceasionally with a median crest; abdomen with five 
segments, anal segment very short. Joints 20 and 21 of right 
anterior antennae fused, inner ramus of posterior antenna rela- 
tively longer than in the female. Blade of mandible, appendages 
on inner border of maxilla, and anterior maxillipeds reduced; 
