Cyclops. 
205 
total length. Antennae 17-jointed, shorter than first. cephalo¬ 
thoracic segment. Abdomen slender, the last segment armed 
on its posterior border with a row of small spines. Furca 
slender, longer than the last two abdominal segments, lateral 
spine at two-thirds the distance from base to extremity. Of 
the terminal setae, the outer is a short blunt spine, the inner 
slender and somewhat longer; the outer median seta rather 
more than two-thirds the length of the inner. 
The armature of the terminal joints of the swimming feet is 
as follows": 
FIRST FOOT. 
Outer br. ex. 3 spines. 
Inner br. 
ex. 
1 seta. 
ap. 2 setae. 
ap. 
1 spine, 1 seta. 
in. 2 setae. 
in. 
3 setae. 
SECOND 
FOOT. 
Outer br. ex. 3 spines. 
Inner br. 
ex. 
1 seta. 
ap. 1 spine, 1 seta. 
ap. 
1 spine, 1 seta. 
in. 3 setae. 
in. 
3 setae. 
* THIRD 
FOOT. 
Outer br. ex. 3 spines. 
Inner br. 
ex. 
1 spine. 
ap. 1 spine, 1 seta. 
ap. 
2 spines. 
in. 3 setae. 
in. 
3 setae. 
FOURTH 
FOOT. 
Outer br. ex. 3 spines. 
Inner br. 
ex. 
1 spine. 
ap. 1 spine, 1 seta. 
ap. 
2 spines. 
in. 3 setae. 
in. 
2 setae. 
The fifth foot is two-jointed. 
The basal joint is very broad 
and is armed with one seta. The terminal joint is armed with 
one seta and a short spine. 
| [ Length about 1 mm. 
Herrick’s® description of C. brevispinosus is so imperfect 
that it is difficult to identify the species with certainty. The 
armature of the swimming feet is different from that in C. par - 
cus, although one might infer from his statement that it is the 
same. The form and armature of the furca, however, is char- 
16—A. & L. 
