572 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [118] 



matter wliat may be the form of the latter. Buoyant eggs seem, in fact, 

 to be much more sensitive to slightly unfavorable conditions than heavy 

 or adhesive ova with thicker membranes. The floating eggs will not 

 stand stagnant sea water for any great length of time, even at a temper- 

 ature of SS^Fahr. Buoyant ova die in the latter, eventually, just as 

 certainly as heavy eggs in standing fresh water at 75°. A few ova to 

 a large amount of water abstract the oxygen much less quickly than 

 where the j^roportion of eggs is in excess of the water. The buoyancy 

 of the cod's egg is undoubtedly due to the diminished specific gravity of 

 the protoplasmic matter of the vitellus, and not to the presence of any oils. 

 In this respect it represents a unique tyi>e of the buoyant ovum. 



