RECENT FRESHWATER INVESTIGATIONS 321 



shallow bodies of water is indicated by a total of 460 species 

 recorded from this lake. The paper contains most valuable 

 observations on the characteristic fauna in each floristic region 

 and on its structural and ecological peculiarities. Zacharias (98) 

 calls the floating fauna of shallow natural or artificial water 

 basins the hdeoplankton and has studied it from a number of 

 places. The majority of limnetic forms recur here and certain 

 Rotifera rare or lacking in lakes are found in such basins. 

 Characteristic is also the abundant development of the micro- 

 phyta and of the Ceriodaphniae. Here also Bigney and Pitard 

 (97a). Fric and Vavra (94) treat of two ponds, of somewhat dif- 

 ferent character, and give a complete and clear picture of pond 

 life, and the changes it undergoes. Here also Ward (98). The 

 characters of a pond are precisely stated by Zacharias (98) who 

 has found in such water basins almost all the eulimnetic organ- 

 isms of true lakes. The Rotatoria are more numerous, and in 

 the phytoplankton the desmids are the chief factor. 



On the fauna of a lake many investigations have been made 

 within the past five years, and the profitless preparation of 

 mere faunal lists seems fortunately to have passed its maximum 

 since an increasing number of the later papers has considered 

 not merely the composition of the freshwater fauna or of one 

 of its groups, in the region studied, but also the biological re- 

 lations and the origin of the fauna. Among the large number 

 of lacustrine investigations of all degrees of completeness, only 

 the more extensive can be mentioned in this connection. The 

 monographic work of Forel on Laka Geneva, Switzerland, has 

 already been sufficiently characterized. Lake Plon, Holstein, 

 has also been extensively studied by Zacharias and his coad- 

 jutors. Garbini's careful investigations on Lake Garda, Italy, 

 and those of Entz and his confreres on Lake Balaton, Hungary, 

 are also deserving of prominent mention. Schwarzsee, Bohe- 

 mia, under Fric, Miigglesee, Germany, under Frenzel, and 

 numerous other individual lakes in Europe have been subjected 

 to careful investigation with valuable results. In North 

 America Reighard has studied Lake St. Clair, Eigenmann 

 Turkey Lake and Ward the northern portion of Lake Michigan 

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