. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHANGE IN SIZE AND SHAPE, AGEING EGGS 189 eggs and the greater the degree of ellipsoidality. This mechanical pres- sure exerts little or no injurious effect. Injury appears to be due to ageing processes within the body of the female. Upon shedding, the mechanical pressure is released, and increasing permeability to water further aids in the return to globular shape. CONCLUSIONS Cyclical CJiaixjc in Size The average size ot freshly-shed eggs, in good physiological condi- tion, varied widely in the 25 females studied, viz., 17
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHANGE IN SIZE AND SHAPE, AGEING EGGS 189 eggs and the greater the degree of ellipsoidality. This mechanical pres- sure exerts little or no injurious effect. Injury appears to be due to ageing processes within the body of the female. Upon shedding, the mechanical pressure is released, and increasing permeability to water further aids in the return to globular shape. CONCLUSIONS Cyclical CJiaixjc in Size The average size ot freshly-shed eggs, in good physiological condi- tion, varied widely in the 25 females studied, viz., 177,600 to 243,100 /r, or per cent. The eggs from any one female varied within much narrower limits, viz., 13,600 to fi3, or per cent. Size of eggs increased with age in all 13 series. The increase may be evident by the third hour and end between 23 and 50 hours. The increase ranged from to per cent. These percentages exclude fused and dead eggs. The minimum and maximum, the mode and average, as well as the number of large eggs, all increased progressively with age. During late ages, size decreased progressively by to per cent. This excluded fragmented eggs. Size increase was accompanied by little deterioration; size decrease by considerable deterioration. Increasing size is attributed to increased water intake; decreasing size to ejection of pellicles and water. The cyclical change in size of control eggs must be known in the determination of the permeability rate. Change in SJmpe Ellipsoid eggs occurred in all 16 females. They ranged from 10 -(- to 62 per cent. The degree of ellipsoidality is given in text. These females were selected for least ellipsoid eggs. Ellipsoid eggs were in excellent physiological condition. With age, eggs became spherical. All eggs were spherical in 8 to 37 hours, and remained spherical thereafter. Shape is not correlated with physiological condition. Ellipsoid shape is attributed to retention of mature eggs within the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
