56 CLARENCE L. TURNER Vol. XXII, No. 2 



but may be recognized by the greater proportion of large sized 

 food animals such as snails, isopods, dragon fly larvae and 

 corixa nymphs. 



Diplesion blennioides passes over the stage of infancy very 

 quickly and begins eating the food characteristic of youth by 

 the 20 mm. stage. There is a strong tendency to take only 

 may fly and midge larvae on the part of the specimens from 

 Lake Erie, while those from the streams pass into a typical 

 maturity in which the diet becomes more complex and large 

 insect larvag are taken. It must be admitted, however, that if 

 complexity of diet is to be taken as a criterion of maturity, 

 Diplesion reaches maturity by the time that it has reached the 

 25 mm. stage. 



Boleosoma ?iignim begins a mixed diet very early (15 mm..). 

 Entomostraca and minute midge larvae continue to appear in 

 the food through life indicating that the habits of infancy are 

 never entirely given up. There is a marked utilization of debris 

 also which does not occur in any other darter except Cottogaster 

 copelandi. 



Cottogaster copelandi. No specimens under 28 mm. in length 

 were examined so that it is impossible to give any data con- 

 cerning the stage of infancy. The period of youth is well sus- 

 tained up to the 43 mm. stage and in addition there is the de- 

 velopment of two habits that mark this group as a specialized 

 one. These habits are the eating of bottom debris and vegeta- 

 tion and the consumption of fish eggs. 



Hadropterus as pro. Nothing can be offered as to the habits 

 of infancy in this fish, but the persistence of copepods, midge 

 larva; and may fly larvae up to 66 mm. specimens points to a 

 retention of the habits of infancy and of youth in the mature 

 stage. It resembles Boleosoma nigrum and Diplesiofi hlefinioides 

 somewhat in this respect. 



Etheostoma. This genus as represented by the three species, 

 flabellare cceriileum and variatiim is characterized in its food 

 habits by its resemblance to the mature game fishes. Vegeta- 

 tion and debris are seldom taken and from the earliest stages 

 (10 mm. in flabellare) they capture and eat food animals that 

 are very large in proportion to the fish eating them. Midge 

 larvae, may fly larvae, beetle larvae and corixa nymphs are some 

 of the animals eaten. E. flabellare shows the greatest degree of 

 specialization in this direction with E. cceriileum resembling it 



