The development of the human body; a manual of human embryology . ht-celled stage; C, sixteen-celled stage; D, early blastula; E, blastula; F, section of blastula.—(Hatscheh.) selves in the form of a hollow sphere which is known as ablastula (Fig. 16, E). The minute amount of yolk which is present in theovum of Amphioxus collects at an early stage of the seg-mentation at one pole of the ovum, the cells containing itbeing somewhat larger than those of the other pole (, B), and in the blastula the cells of one pole are largerand more richly laden with yolk than those of the otherpole (Fig.
The development of the human body; a manual of human embryology . ht-celled stage; C, sixteen-celled stage; D, early blastula; E, blastula; F, section of blastula.—(Hatscheh.) selves in the form of a hollow sphere which is known as ablastula (Fig. 16, E). The minute amount of yolk which is present in theovum of Amphioxus collects at an early stage of the seg-mentation at one pole of the ovum, the cells containing itbeing somewhat larger than those of the other pole (, B), and in the blastula the cells of one pole are largerand more richly laden with yolk than those of the otherpole (Fig. 16, F). If, now, the segmenting ovum of anAmphibian be examined, it will be found that a very 56 THE DEVELOPMENT OF THE HUMAN BODY. much greater amount of yolk is present and, as in Am-phioxus, it is located especially at one pole of the first three planes of segmentation have the samerelative positions as in Amphioxus (Fig. 16), but one ofthe tiers of cells of the eight-celled stage is very muchsmaller than the other (Fig. 17, B). In the subsequent.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
