324 



A. W. BELLAMY. 



for observing disintegration in the unsegmented egg, was to 

 expose the egg soon after deposition, to a temperature of o C. 

 for ten days or two weeks. Fig. 4 illustrates several different 

 stages in the process of disintegration under such conditions. 

 The eggs were deposited in the aquarium (temperature, 6.5 C.) 

 March 26, 9:00-9:15 A.M., and were placed in the refrigerator 

 at 10:00 A.M. On April 7, the eggs were in the condition shown 

 in the figures. The relation of the disintegrated areas to the 

 grey crescent and to the polar axis is obvious. 



(b) Cleavage Stages. The process of disintegration during early 

 cleavage has been studied at low temperature, in KNC, m/i,ooo; 

 m/ioo; HgCl 2 , w/io,ooo; in alcohol, 5 per cent., 8 per cent.; 



a 



FIG. 3. Semi-diagrammatic view of ovarian egg showing the distribution of 

 arteries and veins. The blood vessels were outlined under the camera lucida. 



and incidentally in all of the other agents used to modify de- 

 velopment. The process of disintegration in all of these cases is 

 essentially similar, except in the case of alcohol, which has a 

 marked solvent action on the yolk. In any concentration of 

 alcohol above I per cent., the yolk becomes rough and pitted, 

 an appearance that is much accentuated in the higher concentra- 

 tions (5 per cent, to 8 per cent.). Disintegration usually begins 

 in a meridian that bisects the grey crescent and near the center 

 of the pigmented hemisphere. The surface membranes of indi- 

 vidual cells in this region break down and turn white. Shortly 

 afterward, disintegration begins in the equatorial region just 



