NOTES ON FISHES OF THE DELAWARE RIVER. 845 



phur. The vegetation was quite green beneath the water, and probably 

 had been so throughout the winter. I caught seven specimens of the 

 ditch-pike {Esox porosus) and a vast quantity of the common mud- 

 minnow {Melamira limi.) These two species seemed to be the principal 

 inhabitants of the brook, and, as I expected, the pike each contained in 

 their stomachs a partially digested mud-minnow. Three of the pike 

 proved to be females, and were heavy with a considerable mass of 

 orange-colored eggs, which were nearly matured, I should judge. They 

 were adherent, in three separate masses, and comparatively few in 

 number. An ovum measured ^ of an inch in diameter. 



The largest specimens of the mud-minnows I preserved in an aqua- 

 rium for special study, since completed. I made several dissections of 

 the smaller ones, and found in three, out of twenty examined, very 

 small specimens of their own kind. Cannibalism among fishes is very 

 common, however. The seventeen other specimens were without food, 

 so far as I could detect. The specimens in my aquarium remained 

 without food for two weeks, when the two very large ones devoured 

 their smaller companions. These mud- minnows are wonderfully abun- 

 dant and very prolific, and, like the cyprinoids, are valuable as a source 

 of food for the pike and various percoids. 



This covers the range of my observations made since the 1st of Feb- 

 ruary. There are indications now of spring fairly opening very soon, 

 when I will commence an investigation of the breeding habits of ouf 

 river fishes generally. 



