. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHAETOPTERUS CENTRAL BODIES 161 and became transparent for a moment; in a third the same situation was produced but maintained for a longer time; finally, one slide was so extremely overheated that the ribbon not only melted but bubbled and gave off vapors. In the latter case a number of the eggs have a peculiar glassy appearance in the region of the spindle, the inner zone of the astral rays, and the central body area (Fig. 8). This type, pro- duced by faculty technique, is readily recognized and could not be con- fused wit
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHAETOPTERUS CENTRAL BODIES 161 and became transparent for a moment; in a third the same situation was produced but maintained for a longer time; finally, one slide was so extremely overheated that the ribbon not only melted but bubbled and gave off vapors. In the latter case a number of the eggs have a peculiar glassy appearance in the region of the spindle, the inner zone of the astral rays, and the central body area (Fig. 8). This type, pro- duced by faculty technique, is readily recognized and could not be con- fused with the types occurring under usual ^^i^^^^^m £.-•;;;' W- • V,-j''; /.-'T-V^.v,- -"<-': -* SvMllisiiiif FIG. 8. The glassy type of astral center caused by overheating the ribbon when expanding it. Central bodies were studied in metaphase first-cleavage figures in Chactoptcnis eggs, after using Boveri's picro-acetic fixation. The slide-making procedure was standard, except that the ribbon was overheated when expanding it. Result: The central body area, the inner part of the ray region, and the spindle have a glassy appearance. It can therefore be concluded that when Chactopterus eggs are fixed with Boveri's reagent, the inevitable slight variations in the slide-making procedure do not modify central body structure. While this conclu- sion applies only to the disrupted and even types, it is probable that it also holds true for the other types to be described. GROUP C. TECHNIQUE MODIFIED: PICRO-ACETIC FIXATION VARIED; REGULAR SLIDE-MAKING PROCEDURE Experiment 5. The Effccis of Varying Simultaneously the Amounts of Picric and Acetic Acids When eggs are added to the fixative in a vial, even the densest egg suspension includes some sea water, which slightly dilutes the reagent. The present experiment deals with the effects of a series of dilutions, beginning with one part of distilled water and 99 parts of reagent, and ending with 99 parts of water and one par
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
