Vou.2] Hsterly—Copepoda of the San Diego Region. 181 
tennae reach beyond middle of the furea, joint 19 as long as tenth 
to twelfth, inclusive. Second basal of maxilla with four bristles. 
Inner ramus of first pair of feet 3-jointed, with eight bristles; 
inner ramus of fifth pair reaches almost to the distal border of 
the second joint of the outer ramus; first joint of outer ramus 
much shorter than the third, which is twice as long as the term- 
inal bristle. 
& Terminal portion of grasping antenna (joints 19-25) some- 
what !onger than joints 14-18. Inner ramus of right foot of fifth 
pair straight, with five bristles, which are at the end of the 
terminal joint. 
Coloration: Transparent, with light yellowish pigment in 
various locations. The San Diego specimens showed this to a 
very small extent. 
Length: Female, 1.6 mm.; male a little less. 
Occurrence: June 8, 1904, one male, one female; June 10, 
1904, one male (?). 
Sub-fam. HETERORHABDINAE. 
Heterochaetina Giesbrecht, 1892, p. 63. 
Cephalothorax with five segments; fourth fused with fifth 
thoracic segment; rostral filaments slender, sometimes plumose ; 
last thoracic segment in some cases with pointed lateral angles. 
Abdomen with three or four segments, not always symmetrical. 
Second joint of anterior antennae divided, the two terminal 
joints usually distinet. Second joint of outer ramus of posterior 
antennae divided into two, so that there are as a result eight 
joints in the ramus (which, however, may be reduced by fusions). 
Blade of mandible with few teeth, inner ramus small, sometimes 
lacking. Inner ramus and both distal lobes of inner margin of 
maxilla small, occasionally absent; outer ramus always present, 
and usually much lengthened. Anterior maxilliped elongate, 
lobes small, the proximal ones usually rudimentary; bristles of 
distal lobes, and usually those of the inner ramus, almost always 
long, thick and hooked. The four anterior pairs of feet with 
3-jointed rami, fifth pair like the others, rami almost without 
exception 3-jointed. 
4 Sexual differences in form of body, anterior antennae, fifth 
pair of feet, seldom in structure of mouth parts. Grasping an- 
