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 setfe nearly 

 equal, as are the outer and inner, which are both short. The anteume 

 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 I'obustus Sara. 



I simply quote the original description: 



"Corpus breve et robustum depressiusculum, segmento 1 mo lato et antice ocque 

 rotundato, ceteris ad latera sat exstantibus, ultimo quam segmento 1 mo abdominali 

 multo latiore. Rami caudalesvix divergentes longitudinem segmentorum anteceden- 

 tium 2 superantes setis apicalibus fortibus et fere aculeiformibus, intermediarum in- 

 teriore quam exteriore multo longiore longitudinem abdominis fere ajquante versus 

 medium sparsim dein dense ciiiata, ceteris duabus brevissimis et fere ejusdem longi- 

 tudinis. Antennae 1 mi paris 17 articulatse, breves et crassse segmento 1 mo corporis 

 breviores. Articulus ultimus rami exterioris pedam natatoriorum latus extus aculeis 

 3, intus setis 4 instrnctus; seta marginis exterioris articuli ultimi rami interioris in 

 pedibus 2di — 4ti paris in aculeum fortem conformata; aculeique apicales 2 ej usdem 

 articuli in pari 4to subaequales. Pedum 5ti paris articulus ultimus parvus intus 

 aculeo brevissimo et rudimentari armatus. Sacci oviferi ovales abdomini appressi. 

 Longit. circit. 1,^ mm." 



* Cyclops parous Herrlck. 



Plates XX, Figs. 12-15; XXI, Fig. 22; XXIII, Fig. 8; XXXIV, Figs. 1-8. 



Herrick '82 and '84; Marsb '93. 



This species, which is very near to C. verncdis and C. viridis, has 

 more superficial resemblances to C. xndchellus^ w^hich it also resembles 

 in the form of the swimming feet, occurs in small and stagnant pools. 

 The antennte 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 fioger 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: 



