162 TWELFTH ANNUAL KEPORT. 



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. 



"Antecedentl [C. plialerato] simillimus. Corpus autem minus robustum colore c(b- 

 ruleo vel pottus glauco sat saturate insigne. Segmentum ultirnum thoracicum admar- 

 ginem posteriorem extrosuin pills vel spinulls subtlllssimis peetenatim exoraatum. 

 Kami caudales quam iu 0. plialerato aliquanto longiores, setarum aplcalium interna 

 quam externa multo brevlore, intermecllarum interiore altera fere triple lougiore long- 

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

 tennae 1 -mi paris segraento 1-mo corporis multo brevlores, tenues, artlculis 11 oompo- 

 sitae. Pedes 5-ti paris distincti, uniarticulati, setis 3, quarum Interior ceteris multo 

 major et ciliata, Instruct!. Saccl oviferi parvl abdominl appressl. Longit. circU. yi 

 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-jointed antennae 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 10-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. 



Antennfe 8- jointed. 



Sp. 29. Cyclops fimbriatus, Fischer (fide Rehberg.) 



(Plate R. Fi^. 11.) 



C. erasnicornis, sars, p.radt, herrick. 

 C. gredleri, hkllek. 

 C. pauper, fkic. 



C. poppei, REHBKHG. 



(? C. magniceps, lilljeborg.) 



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 



