ENTOMOSTRACA OF MINNESOTA. 105 



First Feet. 



ex. 1 spine. f ex. 1 seta. 



Outer ramus -j ap. 1 spine, 1 seta. Inner ramus < ap. 1 spine, 1 seta. 



.in. 2 setae. (in. 3 setse. 



Second Feet. 



'ex. 1 seta. Tex. 1 seta. 



Outer ramus -| ap. 1 spine, 1 seta. Inner ramus I ap. 1 spine, 1 seta. 



3 setse. (.in. 3 setse. 



Third Feet. 



1 spine. (ex. 1 seta. 



Outer ramus ■{ ap. 2 spines, 1 seta. Inner ramus -j ap. 1 spine, 1 seta. 



3 sette. (in. 3 setfe. 



Fourth Feet. 



!ex. 1 spine. (ex. 1 seta. 



ap. 2 spines, 1 seta. Inner ramus < ap. 2 spines, 



in. 3 setse. (in. 2 setaj. 



The fifth feet are two-jointed, the basal joint broad, quadrate, with 

 a seta at its outer angle; the second cylindrical, with one long and one 

 short seta at tip. Length, without setiB, 1.34 mm. 



* Cyclops signatus Koch. 



Plates XX, Figs. 8-11, 21; XXI, Fig. 16. 



Jurine '20 (monoculus quadricornis albidus and m. g. fuscus); Kocli '41 (signatus^ 

 and annulicornis) ; Baird '50 (quadricornis var. b and var. c); Claus '57 and '63 

 (coronatus and tenuicoruis); Sars '63 (annulicornis, tenuicornis, and signatus); 

 Lubbock '63 (coronatus, and tenuicornis); Fric '72 (coronatus, and tenuicornis) J 

 Poggenpol '74 (clausii); Uljanin '75; Hoek '78 (coronatus, and signatus) Brady '78 

 (tenuicornis, and signatus); Cragin '83 (tenuicornis, and C. signatus fasciacornis) ; 

 Herrick '82 and '84 (tenuicornis); Daday '85 (tenuicornis, and signatus); Vosseler 

 '86 (tenuicornis, and signatus); Forbes '87 (gyrinus); Sostaric '88 (fuscus); Tball- 

 witz '90; Lande '90; Schmeil '91 (albidus); Brady '91; Richard '91 (fuscus, annul- 

 icornis, and tenuicornis); Schmeil '92 (fuscus, and albidus); Marsh '92; Turner '92 

 (tenuicornis). 



Of the identity of the two varieties which have so long been recog- 

 nized as distinct species (C. tenuicornis and C. coronatus) the writer 

 has little doubt. The development history has been traced sufficiently 

 to settle this point. This combination was first made by the writer, 

 and not by Brady, as Marsh implies. Cephalothorax large and broad, 

 considerably longer than the abdomen. First thoracic segment large, 

 more than half as long as the whole thorax. Abdomen rather short, 

 cylindrical. Stylets short and not tapering, shorter than the preced- 

 ing abdominal segment. SetiE very plumose, three of them long, the 

 longest being about as long as the abdomen, the innermost being 

 nearly half as long and the outermost apical seta short. In the male 

 the first thoracic is much longer and the abdomen relatively shorter. 

 Antennae long and the terminal joints attenuated, the last three being 

 armed by hyaline i)lates. Fourth foot with the following armature: 



