212 Wisconsin Academy of Sciences, Arts and Letters. 



The following species were noted: 



Diaptomus sicilis Forbes. 

 " minutus Lillj. 



Epischura lacustris Forbes. 

 Limnocalanus macrurus Sars. 

 Cyclops fluviatilis Herrick 

 " serrulatus Fischer. 

 Canthocamptus sp. 

 Cypris sp. 



Daphnella brachyura Baird. 

 Ceriodaphnia reticulata Jurine. 

 Daphnia kalbergensis Schoedler. 

 Bosmina sp. 

 Alona glacialis Birge. 

 Leptodora hyalina Lillj. 

 Pontoporeia Hoyi Smith. 

 Mysis relicta Loven. 



There were, besides, several forms of cyclops, which seem to differ from 

 any described American species. As I am now engaged in a study of this 

 genus, I will leave their description for a later publication. None of the 

 species of cyclops which I have found is peculiar to the deep water, as I 

 have found the same forms in the littoral zone of the lake, and in smaller 

 bodies of water in the vicinity. 



The pelagic fauna consists mainly of the following species: Diap- 

 tomus minutus Lillj; Diaptomus sicilis Forbes; Epischura lacustris 

 Forbes; Limnocalanus macrurus Sars; Daphnia kalbergensis Schoedler; 

 Leptodora hyalina Lillj. All of these, with the exception of limnocalanus 

 macrurus, come to the surface at night. The species of cyclops are repre- 

 sented very sparingly, and canthocamptus, daphnella, ceriodaphnia, and 

 alona are quite rare. Evening collections showed vast numbers of 

 diaptomus minutus and epischura lacustris, and in some cases of lepto- 

 dora hyalina. I found bosmina very abundant in November, but rather 

 rare in the summer months. The abyssal Crustacea are cypris, ponto- 

 poreia Hoyi Smith, mysis relicta Loven, and perhaps some of the forms 

 of cyclops. Especial interest, perhaps, attaches to three species of the 

 preceding list. 



Diaptomus minutus Lillj. is found in great numbers, being much 

 more abundant than diaptomus sicilis Forbes. My specimens corre- 

 spond very closely to the description by Lilljeborg, as given in " Revis- 

 ion des Galanides d'Eau Douce," by Guerne and Richard, differing only 

 in the following particulars. The joints of the right fifth foot of the 

 male are shorter and stouter, and the terminal claw is longer and some- 

 what more slender; the lateral spine on the last joint is blunt. The 

 inner ramus of the left foot is more nearly elliptical. The animal aver- 



