Sididae and Daphniidae 215 



0.5 gm. of acid phosphate and a liter of aqueous soil filtrate (water that 

 has been allowed to filter through rich garden soil). 



c. Allow mixture to stand for a day and inoculate with Daphnia. 



5. Aquarium water method. Aquaria that have become very green 

 with a phytoplankton growth furnish a very convenient culture medium 

 for Daphnia. Just remove the fish or transfer the water to another con- 

 tainer and inoculate with Daphnia. This method was recommended to a 

 tropical fish fancier who was having trouble with "green aquaria." He 

 removed the fish, then inoculated with Daphnia; after the Daphnia had 

 multiplied sufficiently to "clear" the aquaria, the fish were put back and 

 had a real feast! 



20 C. is a satisfactory temperature at which to keep these cultures. 



Artemia may also be raised by any of these culture methods. I have 

 kept individual Artemias living for 4 months by using algae. The salt 

 content must be regulated (2 teaspoonfuls to % pint of water). 



If it is desired to cease the Daphnia cultures during vacation periods, 

 it is only necessary to chill or "crowd" the cultures and thus produce 

 ephippial eggs. These may be collected and stored. To hatch them, 

 place outside a window for two weeks of October weather so that they 

 freeze and thaw several times, then place in water to hatch. They may 

 also be artificially frozen in a refrigerator; 8 thaws and freezes give the 

 maximum yield. 



Bibliography 



Banta, A. M. 1921. A convenient culture medium for daphnids. Science 53:557. 

 Bauer, V. 1921. Wie ernahren sich die Wasserflohe. Allg. Fisck. Zeit. Jahrg. 



46:30. 

 Geyer, Hans. 1909. Einige Bemerkungen u. die Zucht von Daphnia. Wochen- 



schrift Aquar.-Terrar. Kde. Jahrg. 26:32. 

 Knorrich, Friedr. Wilh. 1901. Studien ueber die Ernaehrungsbedingungen ein- 



iger fuer die Fischproduction wichtiger Microorganismen des Siisswassers. Forsch. 



Ber. biol. Stat. Blon. 8:1. 



DAPHNIA CULTURE 



Alfred W. Schluchter, Dearborn, Michigan 



THE writer has used several methods which seem to work fairly well. 

 The first is a method similar to that described by Mr. Walter Chip- 

 man.* [See p. 212]. A wheat bran fermentation was used here, instead 

 of cotton seed meal. This was made as follows: About 20 grams of wheat 

 bran was added to 3 liters of water and allowed to ferment for about 

 one week in a moderately warm place. If the Daphnia culture was to be 

 carried out in the open where plenty of sunlight was present, this culture 

 medium was diluted to about 1 to 100 parts of water and then % to % 



* Science 79:59. I934> 



