Sididae and Daphniidae 211 



A NOTE ON BANTA'S CULTURE MEDIUM 



George G. Snider, University of Cincinnati 



AM. BANTA (192 1 )* introduced a culture medium for clado- 

 ♦ cerans which has been, and still is, extensively used. 

 The following modifications of Banta's medium have been used by the 

 writer and found to yield even better results than those obtained from the 

 original directions. First, the manure is collected in a relatively fresh 

 state and permitted to dry thoroughly. It is then added (8 ozs.) to the 

 garden soil in finely divided form as described. Second, after the animals 

 have been in the diluted culture medium (each animal in 100 cc. solution) 

 4 days, 12-15 cc - strained undiluted medium are added. In the case of 

 Daphnia magna this culture medium usually results in animals produc- 

 ing from 15-20 or more young in their first broods. 



CLADOCERA CULTURE 



Harold Heath, Hopkins Marine Station 



THE equipment used in the culturing of Cladocera comprises three 

 aquaria each with a capacity of 16 gallons. After two of these have 

 been filled with water a thin layer of sand is spread over the bottom, 

 and a few aquatic plants are anchored under small stones. At this stage, 

 a cloth sack, containing approximately 8 ounces of sheep manure, is 

 suspended in each aquarium, and the culture is allowed to stand for 

 3 or 4 weeks. Some investigators, I understand, add lettuce leaves from 

 time to time, but so far as my experience goes the ordinary decomposition 

 of the aquatic plants affords, with the fertilizer, a sufficient pabulum for 

 the bacteria and other unicellular organisms which soon appear. Into 

 this mixture a stock of Cladocera is now introduced, and where the 

 manure is renewed each month or so the culture usually flourishes for 

 months, in several instances for more than a year. 



To safeguard against accidents or an unaccountable disappearance of 

 the crustaceans it has been our custom to keep in reserve a third 

 aquarium cultured according to the foregoing method but without Clado- 

 cera. Also in our series approximately % of each aquarium was 

 shaded — though this may not be necessary — and the tank was kept in 

 sunlight where the diurnal temperature ranged from 54° to 74 F. 

 during the year. 



Furthermore, in this region (Monterey Co., Calif.) it is necessary 

 to place a screen over the aquaria to prevent the entry of two types of 

 insects, mosquitoes and back-swimmers (Xotonecta sp.). The first 

 named organisms probably do not interfere with the Crustacea, although 

 it is reasonable to presume that they do diminish the food supply. The 



*A convenient culture medium for Daphnids. Science 53:557. 1921- 



