56 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Pike and pike-perch hybrid (Esox lucius and Stizostedion vitreum.) — 

 Superintendent J. J. Stranahan, of the Putin-Bay, Ohio, station made 

 the following report, dated April 20, 1894, upon an experiment with the 

 grass pike (Esox lucius) : 



Nineteen adult fish were captured, but none of them in spawning condition. We 

 penned the best and although most of them kept well, having been caught in the 

 net by tin teeth, the females refused to yield their eggs and were finally released. 

 On April 22, Mr. John Dischied, of North Bass Island, noticed a grass pike from 

 which the eggs were running freely. He took a quantity, and not having a male ( 

 impregnated them with the milt of a pike perch. * I made my first exam- 



ination of them April 26. They have gone too far to see the segmentation under 

 the microscope, and I am in doubt whether any are alive. There are about 9i eggs 

 to a linear inch, 759 to a cubic inch, measured in water, or 43,832 to the fluid quart. 

 The eggs are of about the same specific gravity as whitefish eggs, and work readily 

 in the McDonald hatching jar, but have very thin membranes, easily ruptured 

 between the fingers. 



Under date of April 28, 1894, Mr. Stranahan forwarded the following 

 additional notes : 



The grass-pike eggs referred to in my letter of April 26 have been examined daily 

 and now show the fish form past doubt. I examined 140 this morning under the 

 microscope and found 40 with the fish formed, or about 28^ per cent. These were 

 worked from the start in a McDonald jar. Those handled in a floating box show a 

 fraction over 20 per cent alive, which leads me to believe that with careful working 

 niuskellunge can be hatched in jars. The developing embryo is unlike any other I 

 have observed. It covers about one-third of the circumference of the egg and has 

 on each side of the body not far behind the head what seems to be an oil drop, 

 nearly equal to the body in diameter. The yolk has no distinct large oil drop, but 

 numerous small ones, pretty evenly distributed over its surface, for which reason the 

 embryo is as likely to be in one position as another, no two apparently assuming the 

 same position. The embryo now covers about two-fifths of the circumference of the 

 yolk. The egg is more opaque than any other I have examined, making its investi- 

 gation difficult. 



On May 4, Mr. Stranahan reported that the above eggs began hatch- 

 ing in small numbers. There were not enough to work well in the jar, 

 the eggs attacked by fungus being hard to separate from the live ones. 

 All the eggs in the floating boxes died and it was estimated that only 

 10 per cent of those in the jar would hatch. The eyes were not dis- 

 cerned until May 3, and then very faintly. 



Yelloio perch (Perca americana). — About the end of April, 1894, Mr. 

 Stranahan took the eggs from a yellow perch weighing 9 ounces. He 

 wrote : 



The eggs came freely in a continuous tube and I used two males for impregna- 

 tion. After swelling the mass was 73 inches long, the tube 3 inches wide (or 6 inches 

 if Hattened out). We find 13 eggs to the linear inch, or 73,000 in all. Impregnation 

 was almost complete. Aside from the fragment used for counting, there do not 

 appear to be 1 per cent of dead eggs. 



On March 20, 1894, the eggs from a yellow per„ch were taken from 

 one of the aquaria in Central Station and placed in a McDonald jar. 

 They developed without perceptible loss (hatching began April 12), 

 and on April 14 about one-tenth of them were out. 



