ENTOMOSTRACA OF MINNESOTA. 113 
each joint has its series of fine teeth. The free lower margins of the 
thorax are ornamented with series of prominences, while the last seg- 
ment is extended into a blunt angle bearing long teeth. The last seg- 
ment of the abdomen is spiny-margined and is ornamented with a 
double row of spines at the anus. The armature of the stylets as well 
as that of the feet is identical with that in typical ©. serrulatus. The 
last two joints of the antenne measure 0.1 mm. each, while the two 
previous measure unitedly 0.12 mm. The color is not opaque as in 
the smaller form usually. Brady’s var. montanus has shorter stylets 
than the type, but seems nearest the small dark form found in peaty 
waters in America. Cyclops pectinifer Cragin has no distinctive points, 
it being typical C. serrulatus. 
Marsh also finds this variety rarely elsewhere than in pelagic local 
ties, and only in occasional association with the type. Schmeil notes 
discrepancies in the original measurements of the two forms, and is 
led to doubt their distinctness. It can only be replied that the distine- 
tions insisted on do actually exist, and are very apparent when the 
forms are before one, and are sufficiently obvious from the measure- 
ments given above. 
Cyclops macrurus Sars. 
Sars ’63; Uljanin ’74 (alajensis); Brady ’78; Rehberg ’80; Sostaric ’80; Herrick ’84; 
Vosseler ’89; Lande ’90; Richard ’91; Schmeil ’91 and ’92. 
This form is so close to C. serrulatus as to suggest the question 
whether it is more than a well-marked variety. From that species it 
differs in the shorter antenne which are hardly longer than the first seg- 
ment, the slender, smooth abdomen, and the greatly elongated stylets, 
which lack the lateral line of teeth. The feet and the proportional 
length of the joints of the antenne are as in serrulatus. The species 
occurs in Scandinavia and Germany, but rarely. 
Cyclops prasinus Fischer. 
Jurine ’20; Fischer ’60; Vernet ’71 (longicornis); Vosseler ’86 (pentagonus); Richard 
’87 (pentagonus var. vichyensis) and ’91 (pentagonus); Schmeil ’91 (pentagonus) 
and ’92. 
Cephalothorax broad, attenutated behind. Abdomen slender, 
nearly cylindrical. Stylets one and one-half as long as last abdominal 
segment. Lateral seta a little distad of the middle. Outer apical seta 
forming a strong spine and about as long as the inner slender seta. 
Longest seta four times the length of the stylet, shorter median seta 
three-fourths as long. Antenna reaching the end of third thoracic 
Segment, proportions and armature as in C. serrulatus. Fifth foot 
one-jointed, closely resembling that of C. serrulatus, but the external 
seta is delicate and not a strong, heavy spine. Ova few, appressed. 
Length 0.8 to 0.9 mm. Color green. 
