VICTOR E. SIIKLFORD. 



(2) Quantity of Food. The quantity of food, like the quality, 

 is one of the reasons assigned for the distribution, migration, and 

 extinction of animals. Although my data on quantity of food 

 in the ponds is not as good as that on quality, a comparison 

 is presented in Table XX IV. 



In the case of the young fishes, the table follows from a com- 

 parison of the tables of Forbes with our own on Entomostraca. 

 The quantity of food for the youngest individuals of all species is 

 practically that of the Entomostraca: Pond I, 32; pond 5<r, 75; 

 pond ja, jj; pond ib, wo. For the adults and young from 

 one inch to four inches in length, an estimate of the quantity of 

 food in each pond for each species has been made by averaging 

 the ratings of the principal articles of food given for each species 

 by Forbes. 



TAULE XXIII. 



METHOD RATING PONDS. Ameiurus natalis. 



The ratings being only estimates, a more accurate method is 

 unnecessary. 



An inspection of Table XXIV shows that the distribution of fish 

 is not correlated with quantity of the foods known to be eaten 

 by that species of fish in other localities. The fish are frequently 

 found only in the ponds where the food is least abundant and no 

 fish is found where its food is most abundant. Are the fish 

 the cause of the deficiency ol their own lood/ To answer this 

 question \\Oll Lake and the small ponds were studied. \\<>l! 

 Lake contains many more fish than any ol the other bodies ol 

 water thus far mentioned, but as it is a large body we cannot 

 compare it with the ponds. Pond I. (see p. 15), which has bci-u 

 artifically separated from \Volf Lake, contains few \\^\\ Ahniniis 

 crysoleucas, Umbra linii, and Ameiurus nebulosus arc the only 

 species and these appear not to be numerous. Pond 1 1. contain- 



