LIST OF CRUSTACEA CLADOCERA FROM . MADISON, 



WISCONSIN. 



By E. A. BIRGE, 



Professor of Zoology, University of ^Wisconsin. 



In 1878 the writer published Notes on Cladocera in the fourth volume 

 of the Transactions of this Academy,* in which were noted twenty-five 

 species of Cladocera found at Madison. Returning to the subject with 

 better means of collecting and a much larger command of the literature 

 of the group, I have been able to enlarge greatly the number of species 

 and to identify them more accurately. As the task of reviewing the 

 greatly scattered literature, especially of the Lynceidce, seems likely to 

 occupy some time, it seems advisable to print a list of the species 

 already found, with notes on rare or new forms. 



A glance at the subjoined list of sixty-four specie- and varieties 

 regarded by many European writers as species, will show how close our 

 fauna is to that of Europe. Out of the whole number, only nine are 

 peculiar to this country and of these five are varieties of species found 

 elsewhere, or are very close to foreign species. Three species are deter- 

 mined as new, Latonopsis occidentalis from the Sididce, Moina sp. nov. 

 from the Daphnidce, Alona lepida from the Lynceidce. 



With the exception of five species and varieties (Daphnia pulex, D. 

 retrocurva, Alona tenuicqudis, and the species of Moina), all of the 

 species in the list have been found in Lake Wingra. This is a small lake 

 about one and three-fourths miles long and half as wide, with broad 

 margins of marsh all around it. In the marsh the water is from a few 

 inches to two feet deep between the areas of wild rice and reeds, and the 

 bottom is partly composed of vegetable debris and partly covered by a 

 dense growth of Chara. The lake itself hardly exceeds fifteen feet in 

 depth, andr almost the entire bottom is overgrown with water plants 

 of various kinds. Among these weeds and in the marshes Cladocera 

 abound. The abundance of food and variety of locality offered probat- 

 ory account for the great number of species. In Lake Mendota, a 

 much larger body of water, six miles by four, and having a depth 

 of sixty to eighty feet, I have found only thirty-eight species of Clado- 



* Vol. IV, 1876-7 (printed 1878), pp. 77-110. PI. I, II. 



