. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 58 FRANK R. LILLIE. globules in the yolk hemisphere is rarer than their formation in the hyaline hemisphere, and was inclined to regard this as evidence that there was a tendency for the eggs to orient themselves in the centrifuge with the vegetative pole away from the center. But I no longer believe that this is the case. The relative rarity of maturation at the distal pole of centrifuged eggs must be due to a different cause, and this is the great resistance of the yolk S&&S&&. FIG. 2. Egg of C/^r/(?//d>
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 58 FRANK R. LILLIE. globules in the yolk hemisphere is rarer than their formation in the hyaline hemisphere, and was inclined to regard this as evidence that there was a tendency for the eggs to orient themselves in the centrifuge with the vegetative pole away from the center. But I no longer believe that this is the case. The relative rarity of maturation at the distal pole of centrifuged eggs must be due to a different cause, and this is the great resistance of the yolk S&&S&&. FIG. 2. Egg of C/^r/(?//d>/'Mjcentrifuged 2,300 revolutions in one minute at a radius of 13 cm., 3 : 57 P. M., June 27, 1906 ; fertilized 3 : 58 P. M., killed 4 : 27 P. M. The formation of the polar globules has taken place at the distal pole. The matura- tion spindle migrated through the entire yolk-mass in the distal hemisphere to reach this position. The sperm-nucleus surrounded by radiations is seen a short distance above the egg-nucleus. The vacuolated area above is the gray cap. , central pole (secondary axis) ; , distal pole (secondary axis). mass to penetration by the spindle. This conclusion is clearly demonstrated by study of series of sections of eggs preserved at regular intervals after centrifuging and fertilizing, which show that many such eggs fail to form the polar bodies at all, or are much delayed, or undergo their maturation divisions within the egg-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory
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