The First Food of the Common White -Fish. 107 



ine tlie subsequent lots in detail, but passed at once to the speci- 

 mens taken on the 23d. Twenty-six of these were examined, and 

 found to have eaten thirty-three individuals of (J yclojis thoin<m, 

 fourteen of Diapiomus ,sici'lis, and fourteen of the minute rotifer 

 already mentioned [Atiunea striata). Two had taken a few diat- 

 oms [Bacillaria) and one had eaten a filament of an Alga. Cy- 

 clops was found in sixteen of the specimens, Diaptomus in nine, 

 and Anurii?a in eight, only two of them being empty. The 

 amount of food now taken by individual fishes was much greater 

 than before, one specimen dissected having eaten two Cyclops and 

 six Diaptomus sicih's, male and female. Another had taken five 

 Cyclops, one Diaptomus and five examples of Afixnea striata. 

 Still another had eaten four of the Cyclops, four Diaptomus, and 

 one Anur;i?a. 



Twenty-five specimens were examined from those removed on 

 the 2-4th of the month, at which time the water of the tank was 

 drawn off and all the remaining fishes bottled. Four of these hatl 

 not eaten, but the twenty-one others had devoured fifty specimens 

 of Diaptomus sicilis, forty-seven of Ci/clops t'/iomasi, fourteen of 

 Anurcea striata, and a single Daphnia hyalina, the latter being 

 the largest object eaten by any of the fishes. A few examples of 

 their capacity may well be given. The ninth example had eaten 

 six Diaptomus, two Cydops thomasi and one Anura?a; the tenth 

 had taken eight Diaptomus, two Cyclops and an Anurj^a; and 

 the twentieth, seven Diaptomus and three Cydojys thomasi. 

 In two of these examples were small clusters of orange globules, 

 probably representing unicellular Algiv. 



Summarizino- these data briefly, we find that of the 106 speci- 

 mens dissected, sixty-three had taken food, and that the ratio of 

 those which were eating increased rapidly, the longer the fishes 

 were kept in the aquarium. Only, one-fourth of those examined 

 on the fourteenth of the month had taken food, while more tlian 

 five-sixths of those bottled ten days later had already eaten. The 

 entire number of objects appropriated by these sixty-three fishes 

 was as follows: Cydops thomasi, ninety-seven; DimpAomus siei- 

 lis, seventy-eight; AnurtMa striata, twenty-nine; Daphnia hyal- 

 ina, one. Seven of the fishes had eaten unicellular Algi\3, two 

 had eaten diatoms, and one, filamentous Algae. 



