The First Food of the Common White -Fish. 101 



fragments of Gammarus and nothing else. Ninety specimens 

 from the same lot were examined February 25, and food was 

 found in fourteen. Four of these had eaten Gammarus frag- 

 ments; two, \-Av\-x of gnats; one, a small Cypris, and eiglit con- 

 tained small fragments of the leaves and stems of vascular plants, 

 including a bit of a netted-veined leaf and a little piece of pine 

 wood. Thirty-nine specimens, the last of the lot, were received 

 March 15, and food was found in fourteen. I dissected nine of 

 these, finding fragments of Gammarus in four, a larva of a gnat, 

 a Chironomus larva, a larva of some undetermined fly, a minute 

 vegetable fragment, a Cyclops, a Cypris, and an undetermined 

 Entomostracan each in one. Three hundred and forty fry from 

 the hatching house were examined in all, in forty-seven of which 

 (fourteen per cent.) more or less food was discernible. Of the 

 thirty-five dissected, eighteen had eaten Gammarus fragments; 

 five, minute insect larvae; four, Entomostraca, and eight, small 

 particles of vegetation. 



Ojdy four lots were received from the spring, on the 9th, 14th, 

 17th, and 25th of February, after which all died of starvation. In 

 the first hundred only one was found which had taken food, and 

 this liad eaten a trace of filamentous Almt? and a minute frao-inent 

 of the parenchyma of some higher plant, with a few diatoms. 

 But one of the second hundred contained even a trace of food, a 

 minute quantity of some thread-like Alga, the cells of which still 

 contained a little chlorophyll. In the third hvmdred likewise, food 

 was found in but one. This consisted of a few particles of veget- 

 able parenchyma, doubtless derived from the decaying plant struc- 

 ture in or around the water. In the third lot of only forty-two 

 specimens, six showed traces of food, consisting almost entirely of 

 a few filamentous Algjt (including a fragment of Oscillatoria) and 

 a little vegetable parenchyma. Desmids and diatoms were ob- 

 served in trivial numbers. 



The total number received from the spring was two hundred 

 and forty-two, of which but eight were found to have eaten any- 

 thing (a little over three per cent, of the whole), and these had 

 taken only Alga^ and vegetable fragments. 



An example of the water of the spring sent me contained many 

 Als"£e but no animals larger than rotifers. The water of the 

 hatchery, being exposed in ponds of considerable size, afforded a 



