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ENTOMOSTRACA OF MINNESOTA. 101 
Cyclops lacustris Sars. 
Cephalothorax sub-ovate, truncate in front. Abdomen of equal 
width throughout; caudal stylets longer than the last two segments of 
the abdomen; terminal sets of moderate size, inner three times as 
long as the outer, internal pair nearly equal. Antenne as long as the 
first two joints of the body. The inner ramus of the fourth foot has 
the exterior spine very small. Second joint of fifth foot small and 
external spine minute. Length 1.5mm. It is suggested by Schmeil 
that this species, with C. scutifer and OC. abyssorum, should be regarded 
as synonyms for C. strenuwus. Upon this matter I can offer no opinion, 
nor does the brief description repeated above help the matter much. 
* Cyclops pulchellus Koch. 
Koch 41; Sars’ 57; Claus ’57 and ’63 (bicuspidatus); Heller ’70 (bicuspidatus); Fric 
’72 (bicsupidatus); Hoek ’78 (bicuspidatus); Rehberg ’80', and 807, (helgolandicus) ; 
Vejdovsky ’82; Herrick ’83 (pectinatus) ; Forbes ’82 (thomasi); Daday ’85 (entzii, and 
pulchellus); Vosseler ’86; Sostaric ’88; Thallwitz ’90; Lande ’90; Schmeil ’91 and 
92 (bicuspidatus); Richard ’91 (bicuspidatus); Brady ’91 (bicuspidatus, and 
thomasi); Forbes ’91 and ’93 (thomasi); Marsh ’93. 
Schmeil and Marsh agree in regarding C. thomasi of America as 
identical with 0. cuspidatus, and in this we are inclined to concur in 
spite of certain differences in variable characters. 
Instead of the original description of Forbes, we reproduce that 
given in the Report on the Invertebrate Fauna of the Yellowstone Park, 
It is to be noticed that Forbes regarded, in his earlier report, certain 
Spines as apical (in his description of the feet) which may be more 
logically described as lateral. 
A long and slender species, with 17 jointed antennz, oval cephalo- 
thorax, somewhat closely articulated, slender abdomen, very long and 
slender caudal rami, and two developed set to each ramus, the 
longer of which is about twice as long as the shorter. 
The cephalothorax is widest near the middle, its greatest width a 
little more than half its length. Posterior angles not prominent or 
produced, except those of the last segment, which are slightly pro- 
duced outwards. Sides of the first segment subparallel, rounding 
slightly toward the front, the segment itself twice as long as the other 
segments combined; the second segment shorter than the third, but 
longer than the fourth; the fifth reduced to a narrow linear band, as 
seen from above, the extremities of which project a little beyond the 
lateral outline. Abdomen with furca, a little shorter than the 
cephalothorax, its greatest width one-fourth of its length, including 
furca. First segment in the female as long as all the others together, 
broadest in front, its lateral outlines emarginate behind the anterior 
angles. Posterior margin of last segment serrate beneath and at sides; 
