Vou.2] Esterly—Copepoda of the San Diego Region. 145 
4 Anal segment very short, abdomen with five segments. 
Anterior antennae 20-jointed, joints 8-10, 12 and 13, 20 and 21, 
24 and 25 fused. Blade of mandible, appendages of inner border 
of maxilla and anterior maxilliped stunted. Left fifth foot uni- 
ramous, 5-jointed; right lacking; swimming feet as in female. 
1. Aetideus armatus Brady. 
Aetidius armatus Brady, 1883, p. 75, pl. 10, figs. 5-16. 
Aetidius armatus Giesbrecht, 1892, p. 213, pl. 2, fig. 6; pl. 14, 
figs. 1-13; pl. 36, figs. 6-9. 
Aetideus armatus Giesbrecht, 1898, p. 31. 
Aetideus armatus Wolfenden, 1903, p. 266. 
Fig. 14.—Aetideus armatus. Female. (a) Animal from side X20. (6) 
Second foot X83. St., terminal bristle of outer ramus. 
With the characters of the genus. 
Coloration: Rather transparent; there was no pigment in my 
specimens, but Giesbrecht says that red may occur in the body. 
Leneth: Female, 3 mm. 
Occurrence: San Diego, June 9, 1904, one female; June 14, 
two females. 
2. Genus Gaidius Giesbrecht. 
Gaidius Giesbrecht, 1895, p. 249; 1898, p. 32. 
Gaidius Wolfenden, 1902, p. 365; 1903, p. 266; 1904, p. 114, pl. 
iO), eS 1G tsk 
Rostrum short, one point (fig. 15b), sides of last thoracic seg- 
ments produced into a sharp spine (fig. 15a). Inner ramus of 
posterior antennae three-fourths as long as outer. Outer ramus 
of first foot 2-jointed, of the second to fourth 3-jointed, inner 
ramus of first and second feet 1-jointed, of the third and fourth 
3-jointed. | 
