The Journal of experimental zoology . other,as I learned from thestudy of living 8 is a section throughthe same fragment repre-sented in Fig. if. Theentire cytoplasm ispacked with large yolkgranules, which look as if ,; they were crowded together by the central accumulation of hyalo-plasm. They stain very dariy>nd re^is(t^ e?itraction by the iron-alum solution for a considerable length of time. In fact, whenthese granules become dark blue both the rays and centriolesare found completely decolorized. At the center there is a largeclear area of almost the size of the germinal v
The Journal of experimental zoology . other,as I learned from thestudy of living 8 is a section throughthe same fragment repre-sented in Fig. if. Theentire cytoplasm ispacked with large yolkgranules, which look as if ,; they were crowded together by the central accumulation of hyalo-plasm. They stain very dariy>nd re^is(t^ e?itraction by the iron-alum solution for a considerable length of time. In fact, whenthese granules become dark blue both the rays and centriolesare found completely decolorized. At the center there is a largeclear area of almost the size of the germinal vesicle. In it sometwo or three dozens of cytasters are seen, most of them beingsituated near the periphery. Each aster bulges out a little toward t:. •?/???> ^ fes*;^^^* Fig. Ill (X913). 6, Section of an enucleated fragment, in which severalcytasters have been produced^ by CaCl2 solution; fourcytasters are seen inthe sectioh; the centrioles of the twocvtasters are in the next section. 296 JSfaohide Tatsu. 7 *• • •. Fig. rV (X903). 7, Section of an enucleated fragment, in which a singlecytaster has made its appearance. Notice enlarged centrosomeand many centrioles in it. <?, section of the enucleated frag-ment, represented in Fig. if, with central clear area containingmany cytasters and yolk-islands. the yolk part, so that insections as many inden-tations are present asthe number of intervalsbetween two asters. Itshould be noted thatthe yolk granules nearthe clear space in overextracted preparationsshows a radial arrange-ment (Dotterstrahlungof Hacker), and clearstreaks run betweenthe rows of yolk gran-ules. These streaks,however, do not go farinto the yolk layer. In both the types aand c the structure ofthe cytasters is verysimilar, so much sothat it is hardly neces-sary to describe themseparately. The onlydifference betweenthem lies in that inthe type a the rays aremuch stronger thanthose of the type of the cytastersare drawn with ahigher power. Fig. 9aand
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Keywords: ., bookauthorwi, bookcentury1900, bookdecade1900, booksubjectzoology
