ENTOMOSTRACA OF MINNESOTA. 93 
Cephalothorax rather long, tapering caudad, fourth and fifth seg- 
ments somewhat produced. Abdomen more than half as long as 
thorax, first segment as long as the remainder. Stylets as long as the 
two preceding segments plus half the next. Median apical set nearly 
equal, as are the outer and inner, which are both short. The antenne 
are shorter than the first thoracic segment, either 17-jointed or 18- 
jointed by the subdivision of the seventh joint. Schmeil claims to have 
found some in which the right antenna is in one condition and the 
left in another. Fifth foot two jointed, basal segment short, broad, 
bearing a plumose hair; second joint small, cylindrical, armed with a 
short spine and a plumose seta. Receptaculum opening transversely 
narrowly elliptical. Length 1.2 to 1.7 mm. 
Cyclops robustus Sars. 
I simply quote the original description: 
‘*Corpus breve et robustum depressiusculum, segmento 1 mo lato et antice eque 
rotundato, ceteris ad latera sat exstantibus, ultimo quam segmento 1 mo abdominali 
multo latiore. Rami caudales vix divergentes longitudinem segmentorum anteceden- 
tium 2 superantes setis apicalibus fortibus et fere aculeiformibus, intermediarum in- 
teriore quam exteriore multo longiore longitudinem abdominis fere «quante versus 
medium sparsim dein dense ciliata, ceteris duabus brevissimis et fere ejusdem longi- 
tudinis. Antenne 1 mi paris 17 articulatz, breves et crassze segmento 1 mo corporis 
breviores. Articulus ultimus rami exterioris pedum natatoriorum latus extus aculeis 
3, intus setis 4 instructus; seta marginis exterioris articuli ultimi rami interioris in 
pedibus 2di—4ti paris in aculeum fortem conformata; aculeique apicales 2 ejusdem 
articuli in pari 4to subequales. Pedum 5ti paris articulus ultimus parvus intus 
aculeo brevissimo et rudimentari armatus. Sacci oviferi ovales abdomini appressi. 
Longit. circit. 14 mm.’’ 
* Cyclops parcus Herrick, 
PLATES XX, Fi@s. 12-15; XXI, Fie. 22; XXIII, Fic. 8; XXXIV, Fies. 1-8. 
Herrick ’&2 and 734; Marsh ’93. 
This species, which is very near to C. vernalis and C. viridis, has 
more superficial resemblances to C. pulchellus, which it also resembles 
in the form of the swimming feet, occurs in small and stagnant pools. 
The antenne are shorter than or about as long as the first thoracic 
segment, the last two segments of which are acute. The antennules 
are rather short. Labrum narrow, projecting below into obtuse angles, 
cutting edge with nine small teeth. The terminal joint of the larger 
branch of the maxilliped bears four hairs. The second joint has a 
moderately large dactyl, the movable finger of which is small and 
sparsely spiny, the immovable finger is ornamented by an oblique 
series of blunt prominences and a small seta at its base. The arma- 
ture of the swimming feet is as follows: 
