96 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. : 
Cyclops uniangulatus Cragin. 
Cragin ’88; Herrick ’84. 
Cragin was not conversant with the description of C. parcus, with 
which his description agrees save in one point. It differs from C. 
parcus in having three inner sete on the terminal joint of the outer 
ramus of the first foot. It would be officious to suggest a possible 
oversight here, but C. parcus has only two in type specimens (though 
in all this group the corresponding ramus of the second foot has three 
sete), so that at present the two must be kept distinct. 
* Cyclops leuckarti Claus. 
PLATES XVI; XVIII, Fies. 1, A-J; XXIV, Fias. 2-6. 
Claus ’57 and ’63; Sars ’63; Poggenpol ’74 (simplex); Uljanin ’75 (tenuicornis); Hoek 
78 (leeuwenhcekii); Herrick ’83 (tenuissimus) and ’84 (simplex and leuckarti); 
Daday ’85 (simplex, pectinatus, and leuckarti); Vosseler ’86 (simplex); Herrick 
’87 (simplex); Thallwitz ’90 (simplex); Lande ’90 (simplex); Schmeil ’91 and ’92; 
Richard ’91; Forbes ’91 (edax); Brady ’91 (scourfieldi); Marsh ’92. 
‘‘DESCRIPTION OF THE FEMALE: The form is very slender, an 
average individual measuring between 0.95 and 1.0 mm. exclusive of 
the caudal sete. The following detailed measurements of a specimen 
measuring 0.976 mm. will serve to exhibit the proportions of the parts: 
First thoracic segment 0.30 mm., second segment 0.08 mm., third seg- 
ment 0.08 mm., fourth segment 0.056 mm., fifth segment 0.024 mm.; 
first (apparent) abdominal segment 0.16 mm., second segment 0.08 
mm., third segment 0.048 mm.; caudal stylets 0.088 mm., outer seta 
0.08 mm., outer median 0.30 mm., inner median 0.46 mm., inner 0.20 
min., dorsal 0.06 mm.; the lateral seta is 0.036 mm. from the end. 
The antennie reach nearly to the base of the thorax when reflexed, and 
are quite strong. They resemble those of C. tenwicornis in several par- 
ticulars, but since it is desirable to distinguish this species with the 
greatest possible accuracy, the following numbers are given to express 
the relative length of the several segments, beginning with the first: 
120, 25, 33, 410, 57, 64, 11, 95, 95, 105, 117, 127) 159 146, 1510, 1615, 
1714. The fourth, eleventh, fourteenth and fifteenth segments bear 
the longest setee. The last two segments are armed with a knife-like 
ridge similar to that found in C. tenuicornis. This ridge is serrulated 
on the last segment, and near the end is cut by a deep incision so that 
the terminal part is like a hook notched upon its convex outer part. 
The antennules are slender and but moderately spinous, the first 
three segments being almost exactly equal (0.06 mm.), while the ter- 
minal segment is as long as the basal segment of the antenne (0.08 
mm.). The labrum is armed with thirteen small teeth. The larger 
maxilliped is pearled on the posterior margin of its largest segment. 
The armature of the terminal joints of the feet is as follows: 
