64 



I4th, one hundred specimens were removed, and twenty-seven 

 of these were dissected. Twenty were empty, but the remain- 

 ing seven had already taken food, all Cyclops or Diaptomus. 

 Three had eaten Cyclops only, and six Diaptomus, while two 

 had eaten both. Fourteen of these Entomostraca, seven of 

 each genus, were taken by these seven fishes. From those 

 captured the next day, twenty-five specimens were examined, 

 of which nineteen were without food. Of the remaining six, 

 three had eaten Diaptomus and three Cyclops ; five of the 

 former being taken in all, and ten of the latter. Three specimens 

 were next examined from those caught on the 19th of March, 

 two of which had devoured Diaptomus, and a third a single 

 Cyclops thoiiiasi and a shelled rotifer, Aniircea striata. The 

 character of the food at these earliest stages was so well settled 

 by these observations that I deemed it unnecessary to examine 

 the 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 Cyclops 

 thoinasi, fourteen of Diaptomus sicilis, and fourteen of the 

 minute rotifer already mentioned {Aftiircea striata). Two had 

 taken a few diatoms (Bacillaria), and one had eaten a filament 

 of an Alga. Cyclops was found in sixteen of the specimens, 

 Diaptomus in nine, and Anuraea 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 sicilis^ male and 

 female. Another had taken five Cyclops, one Diaptomus, and 

 five examples of AnurcFa striata. Still another had eaten four 

 of the Cyclops, four Diaptomus, and one Anuraea. 



Twenty-five specimens were examined from those removed 

 on the 24th of the month, at which time the water of the tank 

 was drawn off and all the remaining fishes bottled. Four of 

 these had not eaten, but the twenty-one others had devoured 

 fifty specimens of Diaptomus sicilis, forty-seven of Cyclops 

 thomasi, fourteen of Anuraea 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 Cyclops 



