STATE GEOLOGIST. 221 



1. CyclopiDtE of Mtn^i^esota, with notes on other Copepods. 



CALANIDuS. 



It ee ms that recent authors have sufficient ground for uniting the 

 families (7a/amc?(S and Po??^^//ir/o5 under the single name; the value of 

 these terms as subfamily names even may be questioned. 



The family is represented in our limits by two genera and by three, 

 or doubtfully more species. 



The fifth pair of feet furnishes, by its modifications, the best criteria 

 for distinguishing genera and species. 



Genus Diaptomus, Westwood. 



Body elongated, compressed; head destinct from the thorax, anterior 

 antennse 25-jointed, those of the male geniculate on the right side; 

 posterior antennae and mouth parts as in Calanus ; in.ner branches of 

 all the swimming feet three-jointed except the first, which is two- 

 jointed; fifth foot consisting of two unequal branches, prehensile; 

 abdomen of male with five-joints, of female three-jointed. 



Diaptomus castok. 



(Plate I, figs. 1-7, Plate II, figs. 1-2, 16.) 



BibUographij. 

 Monoculus castor, Jurine. 



Cyclops castor, Desmarest, Baird, Mag. Zool. and Bot. 

 Cyclops cseruleus, Midler, Latreille, Bosc. 

 Monoculus cseruleus, Fahricius, Manuel, Gmelin. 

 Cyclops lacinulatus, Muller, Bamdohr, Latreille, Bosc, Baird, Trans. 

 Beow. club. 

 Monoculus lacinulatus, Manuel, Gmelin. 

 Cyclops rubens, Midler, Latreille, Bosc, Baird, 

 Diaptomus castor, Westivood, Baird, Baker. 

 Cyclopsina castor, .1/. Edivards, Baird, Glaus. 

 Grlaucea rubens, Koch, Deutschlands Crust. 

 Glaucea caerulea, Koch, an 



Diaptomus castor, Baird, Brit. Entom. 



Glaus, Die Freilebenden Copepoden. 

 Lilljehorg, De Crust, ex ord. trib. 

 Lubbock, Trans. Linn. Soc. 

 westwoodii, Lm^^ocA:, " 

 castor, Fric. Die Krustenthiere Bohmens. 

 castor, Brady, Brit. Copepoda. 



