162 University of California Publications. | ZooLoGy 
acuta. Three or four females were taken during June and July, 
1904. 
The specimens which I have placed in this species correspond 
to Giesbrecht’s descriptions; but the females have hairs on the 
ventral sides of the abdominal segments, and Giesbrecht does 
not mention these nor figure them (1892, pl. 37, figs. 39, 40). The 
outer marginal lobe of the maxilla is always provided with eight 
bristles, but one of these is very inconspicuous and much shorter 
than the others. As these animals correspond very closely in 
other respects to Giesbrecht’s specimens, especially in the form of 
the genital segment, I have thought best to include them under 
his species, even though there are slight differences. 
Sub-fam. SCOLECITHRICIN AE. 
Scolecithricina Giesbrecht, 1892, p. 55. 
2 Head commonly fused with first, and fourth with fifth 
thoracie segment; rostrum with two usually soft filaments; abdo- 
men with four segments, symmetrical. Eighth and ninth joints 
of anterior antennae always fused, and occasionally other joints. 
Outer ramus of posterior antennae 6-jointed. Blade of mandible 
with weak teeth; inner ramus of maxilla fused with second basal. 
The distal bristles of the anterior maxillipeds are modified into 
sac-like structures (fig. 306), which occasionally are pencillate 
at the end; lobes of appendages closely crowded together. Inner 
ramus of posterior maxillipeds at most only as long as the second 
basal. Inner rami of swimming-feet jointed as in the Clauso- 
calaninae and set with spines; fifth foot rudimentary or absent. 
& Abdomen with shortened anal segment, number of joints 
of anterior antennae reduced, the twentieth and twenty-first 
often fused only in one. Other head appendages like those of 
the female, or specifically modified. Left fifth foot 5-jointed, 
oceasionally with inner ramus, the right 4-jointed (rudiment of 
inner ramus sometimes present) or lacking. 
a 
