Vot.2] Hsterly.—Copepoda of the San Diego Region. ek 
rorhabdinae) : stunting of the second and third inner marginal 
lobes of the maxilla through lengthening of outer ramus; pre- 
ponderance of distal bristles of anterior maxilliped over the prox- 
imal. The four. anterior pairs of feet with 3-jointed rami; 
but in Temora the number of joints is reduced through fusion. 
The fifth pair of feet is like the others (inner marginal bristle 
of second joint of outer ramus of special form, sword-shaped, 
awl- or thorn- lke) or rudimentary, inner ramus 1-jointed or 
lacking, outer ramus 1- to 3-jointed. 
4 Abdomen with five segments, anal segment rarely short- 
ened; genital orifice and grasping antenna on opposite sides of 
the body. Grasping antenna right or left, joints 19 to 21, and 22 
to 23 fused. Both feet of fifth pair present, inner rami complete 
or reduced to absence; outer rami forming hooks or forceps. 
Sheght sexual differences occasionally in form of last thoracic 
segment and swimming feet. 
Sub-fam. CENTROPAGINAE. 
Centropagina Giesbrecht, 1892, p. 59. 
2 Cephalothorax with six segments, abdomen with three ; ros- 
tral filaments soft. Anterior antennae (24th and 25th joints 
fused), mandibles and maxilla as in Calanus; the length of the 
distal curved bristles of the anterior maxillipeds and the heavily 
bristled first basal of the posterior maxillipeds is characteristic. 
All five pairs of feet with 3-jointed rami. 
& Grasping antenna on the right side; outer ramus of left 
fifth foot 2-jointed; the right foot with forceps. 
1. Genus Centropages Kroyer. 
Centropages Kroyer, 1849, p. 602. 
Catopia Dana, 1848, p. 25; 1849, p. 280; 1852, p. 1172. 
Hemicalanus Dana, 1852, p. 1103. 
Ichthyophorba Lilljeborg, 1853, p. 184. 
Tiaptomus Lubbock, 1857, p. 403. 
Ichthyophorba Claus, 1863, p. 198. 
Centropages Brady, 1883, p. 81. 
Centropages Giesbrecht, 1892, pp. 59, 303, 731; 1898, p. 53. 
Centropages Wheeler, 1899, p. 172. 
Centropages Thompson and Scott, 1903, p. 247, pl. 1, figs. 19-25. 
2 Head separate from thorax, fourth thoracic segment from 
fifth. Abdomen with three segments, genital segment asymmet- 
