Journal of experimental zoology . lutioneggs at a comparatively latestage of differentiation. Anegg is occasionally foundthirty to forty-five hoursafter the beginning of theexperiment that shows nosegmentation and no cilia-tion but is undergoing extra-ordinary ameboid an egg has a generalopaque appearance but theborder is clearer than therest of the egg. The smallpseudopodia sometimesform and disappear veryquickly. In Text-Fig. V are shown camera lucida drawings of anegg of this kind forty-three hours after the beginning of theexperiment. In the first two rows, a-h, are eight suc
Journal of experimental zoology . lutioneggs at a comparatively latestage of differentiation. Anegg is occasionally foundthirty to forty-five hoursafter the beginning of theexperiment that shows nosegmentation and no cilia-tion but is undergoing extra-ordinary ameboid an egg has a generalopaque appearance but theborder is clearer than therest of the egg. The smallpseudopodia sometimesform and disappear veryquickly. In Text-Fig. V are shown camera lucida drawings of anegg of this kind forty-three hours after the beginning of theexperiment. In the first two rows, a-h, are eight successivesketches made at one-half minute mtervals; in the third andfourth rows, i-p, are sketches made eleven minutes later of thesame egg at one-fourth minute intervals. These drawings donot show more than half the forms that were taken by this eggduring the time the sketches were being made. The peculiardifferentiation just described may be correlated, I believe, withprocesses found in the normal larvas of about the same age. By. Fig. V. Camera drawings to show rapid ameboidmovements. From a calcium nitrate solution, forty-three hours old. Sketches made at one-half minute inter-vals, a-h; sketches at one-quarter minute intervals, i-p. Partheno^enetic Development of Amphitrite 73 the time the trochophore is forty hours old it has developed threeor four well-defined body segments. During this development instructure a physiological differentiation has occurred so that thelarva is now able to make comparatively quick, jerky and wrig-o-line movements. I think without doubt that this is the sort ofdifferentiation that takes place in these eggs treated with salt-solutions. The protoplasm presents the same medium-opaqueappearance and the movements possess the same general character. B Description of the Preserved MaterialI. Early Stages If the eggs are quite ripe, that is, in a condition to be fertilized,a study of the sections of unfertilized parthenogenetic eggs dis-closes no abnor
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1904
