162 TWELFTH ANNUAL REPORT. 



mm.; abdomen, 0.44 mm.; stylets, .06 mm.; longest seta, 0.34 mm.; 

 antennae, 0.28 mm.; width of thorax, 0.44 mm, 



Cyclops affinis^ Sars. 



" Antecedent! [C. phalerato] simillimus. Corpus autera minus robustum colore coe- 

 ruleo vel potius glauco sat saturato insigne . Segraentum ultimum thoiacicum ad mar- 

 ginem posteriorem extrosum pilis vel spinulis subtilisslrais peetenatim exornatum. 

 Rami caudales quam in C. phalerato aliquanto longiores, setarum apicalium interna 

 quam externa multo breviore, intermediarum interiore altera fere trlplo loHgiore long- 

 itudinemque abdominis superante, in medio aculeata deln vero subtile ciliata. An- 

 tennae l -mi paris segmento 1-mo corporis multo breviores, tenues. articulis 11 compo- 

 sitae. Pedes 5-ti paris distinct!, uniarticulati, setis 3, quarum interior ceteris multo 

 major et ciliata, instruct!. Sacci ovifer! parvi abdomini appressi. Longit. circit. % 

 mm." 



Cyclops ornatus^ Poggenpol (=C. clausii, Heller, fide Rehberg,) is 

 almost certainly, in our judgment, a young or atavic condition. 



C. helleri^ Brady, though not identical, is no more worthy a spe- 

 cific name. If every form with eleven-joiuted anteuDae and egg- 

 sacs be worthy a distinct name, it will be possible to duplicate all 

 the seventeen-jointed forms. Fortunately, however, many species 

 agree together in this condition, so that the number of spurious 

 species derived from this source is rather small ; among these is to 

 be reckoned C. nanus^ Sars, which is obviously very near the pul- 

 chellus group. 



Antennae lO-jointed. 



No valid species have permanently 10-jointed antennae. C. pha- 

 leratus is frequently found with 10-jointed antennae. C. kauf- 

 raanni is without much doubt an immature form. 



Antennae 8-jointed. 



* Sp. 29. Cyclops finibriatus, Fischer (fide Rehberg.) 



(Plate R. Fi^. 11.) 



C crassicornis, sars, brady, herrick. 

 C. gredleri, hkller. 

 C. pauper, fric. 



C. poppei, REHBERG. 



{f C. magniceps, ulljeborg.) 



Our American species corresponds to that described by Rehberg 

 as a new species. The differences mentioned in the previous report 

 (see Cyclopidae of Minnesota, p. 233) are just those which have 

 led Rehberg to establish the C. poppei, which, by the way, was 



