ENTOMOSTRACA OF MINNESOTA. 115 
dimorphic states are very distinct and seem, in part at least, to be 
governed by habitat. The colors are frequently brilliant, varying 
from deep indigo to greenish brown. The coloring matter is some. 
what irregularly distributed but is most persistent between the bases 
of the feet, in the last segment of the abdomen and in the last joints 
of the antenne. 
The full-grown female measures about 0.70 mm., the males being 
more slender. Oviferous females often have the fourth pair of feet 
with two-jointed rami. American authors find the species pelagie, 
and Brady, though he found it in ditches immediately connected with 
large sheets of water. 
Marsh notes that there is a resemblance between this species and 
C. pentugonus Vosseler. 
Cyclops capillatus Sars. 
‘*Cephalothorax sub-ovate; anteriorly uniformly rounded; seg- 
ments projecting somewhat laterally, the last being scarcely wider 
than the first abdominal segment. Abdomen attenuated posteriorly; 
caudal rami almost as long as the last three abdominal segments, 
hardly divergent; the external and internal apical setze short and 
nearly equal, the interior of the median setze as long as the abdomen, 
lateral seta about in the middle of the stylet. Antenne of the first 
pair robust, slightly exceeding the first segment of the body when re- 
flexed, with the twelve joints densely covered with long and divergent 
hairs. The last joint of the outer rami of swimming feet are elongated 
and armed externally with three spines, internally with four setie; the 
interior apical spine of the interior rami of the fourth pair of feet 
longer than the exterior. Feet of the fifth pair large, with a large 
and thick basal segment and a small oval second joint bearing one 
long seta and a short spine. Ovisaecs small, narrow and divergent. 
Eye very small. Length nearly 2.0 mm.” 
Very close to (. viridis in many points. Found only in Sean- 
dinavia. 
Cyclops crassicaudis Sars. 
Cephalothorax elongate-ovate; segments produced laterally, espe- 
cially the last, which extends into a somewhat procurved process. 
Abdomen short and thick, first segment somewhat excavated; caudal 
rami equaling the last two segments of the abdomen. HExternay 
apical seta longer than the internal, both short; median setie long. 
Antenne of the first pair 12-jointed, scarcely longer than the first 
Segment. Swimming feet short and thick, spines and sete short; the 
interior apical spine of the last joint of the inner ramus of the fourth 
8 
