104 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
Rudimentary legs of fifth pair distinctly articulated, basal article 
with a long seta at its outer distal angle, and second article with two 
sete at its blnnt tip, the outer the longer. From Duck lake. 
Neither figures nor measurements are given, and the form of the 
fifth foot is left to conjecture. In this difficult section of the genus 
it is very hard to place species even when all the details are clearly 
before us. The original description is reproduced with only verbal 
alteration for the sake of brevity. 
* Cyclops forbesi Herrick. 
Forbes 93 (serratus*). 
A very long, narrow, loosely articulated species with strikingly 
salient thoracic angles. Cephalothorax broadest far forward and 
lobed in front, between the 17-jointed antenne. Abdomen long and 
slender, with very long and narrow caudal rami, and but two devel- 
oped sete to each ramus. The first segment is but little longer than 
wide (eight to seven), is broadest across the middle, and excavate in 
front at the base of each antenna, leaving a thick, median, projecting 
lobe. The second segment is nearly a fourth as long as the first, and 
but little narrower, broadest across its posterior angles, which, though 
blunt, are so strongly salient that the lateral margins are decidedly 
sinuate. The third segment is. as long as the second, but narrower, 
and with its sides more nearly parallel. The fourth and fifth seg- 
ments are progressively shorter and narrower, the latter being trape- 
zoidal, as seen from above, and separated from the first abdominal 
segment by a deep acute emargination. 
The abdominal segments areas long as the cephalothoracic segments 
two to five taken together, and the furca is as long as the last three 
segments. The first segment of the abdomen is broadest in front, 
where its width is nearly as great as its length. The second is as 
broad as long, the third and fourth equal, the fifth a little shorter, the 
last with a row of fine spinules around the base of the rami. The 
width of each ramus is contained nearly eight times in its length. 
Besides the lateral spine, situated a little before the posterior third of 
the ramus, there is a cluster of two or three minute spines at its an- 
terior fourth. The outer and inner terminal sets are reduced to short 
subequal spines about twice as long as the ramus is wide. The other 
setee are slender, plumose, the inner nearly twice as long as the outer. 
The antennz are rather stout and short, 17-jointed, reaching to the 
end of the second segment. They are without special structures or 
appendages. [This probably means armed as usual, but without 
knife ridges or spurs.] Armature of the legs as follows: 
* This name is preoccupied by C. serratus Pratz. 1866. 
