488 
DR. W. H. RANSOM ON THE OVUM OF OSSEOUS FISHES. 
ceased to move, except two or three which lay near a very minute air-bubble. Twenty- 
nine hours after, all were still, the yelk-ball was round, the discus proligerus was not 
detached but flat and diffused. 
Experiment j was the same as the above, with only seven eggs in the cell. Twelve 
hours after, the eggs were contracting freely, and resembled the control eggs more than 
those in cell h. In twenty-three hours the movements were languid, but distinct. After 
twenty-nine hours the contractions were barely visible. In this cell there was no air- 
bubble. 
Experiment e' was the same as experimant e, with forty-eight impregnated eggs in 
the cell. After four hours the germinal mass was cleft into two or four. After twelve 
hours it was cleft into eight or sixteen masses, the control experiment 3' being at the 
same time in the coarse mulberry stage, containing hundreds of cleavage masses. The 
germinal mass was flat and rather diffused, and the outlines of the separate cleavage 
masses indistinct, as if they were about to coalesce. The eggs looked granular, notably 
the germinal mass. The yelk-ball went on contracting, however, although not so 
strongly as in experiment e. After twenty-three hours the cleavage had not progressed, 
the yelk-ball continued to contract in a few eggs with still further impaired vigour ; but 
in most eggs it was round and still. After twenty-six hours all were motionless, and the 
yelk-ball so relaxed as nearly to fill the yelk-sac. These appearances reminded me of 
those which resulted from the action of carbonic-acid water on the eggs of the stickle- 
back. Into this cell a little air entered. 
Experiment f was the same as the last, with seventeen eggs only in the cell. After 
twelve hours they were in a coarse mulberry stage of cleavage, being, however, less 
advanced than the control ova, but more than those of experiment d ; the yelks were 
contracting freely. Twenty-three hours after, they were in a finer mulberry stage, and 
were well contracting. Thirty-five hours after, the germinal mass had become diffused 
and darkly granular, but the contractions of the yelk continued. Fifty-three hours 
after, all were motionless. There was an air-bubble in the cell. 
Experiment g' was the same as the last, with only ten eggs in the cell : air-bubbles 
entered again. Twenty-three hours after, the cleavage was further advanced than in 
experiment f, but not so far as in the control experiment 3 ; the yelks contracted 
freely, however. Thirty-five hours after, they had dark, granular, germinal masses 
and contracted slowly. After fifty-three hours all were still. 
Experiment U was the same as the last, with thirty-eight eggs in the cell, and tallow 
employed instead of wax as a luting. After twelve hours they were cleft in eight, the 
cleavage masses were dark, granular, and almost fused together ; the contractions, 
however, were distinct. After twenty-three hours the cleavage had not progressed, the 
contractions were languid. After twenty-nine hours the cleavage masses were quite 
fused, the contractions had ceased, the yelk-ball was round, relaxed, and at rest. In 
this cell there were no air-bubbles. 
Experiment/. — The same as the above, with only seven eggs. After twelve hours 
