. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. FIG. 104.—Unequal segmentation of the Frog's tgg (after Eckeij in ten succe^ve stages. and larger portion, in which the segmentation proceeds much more slowly than in the former. In partial segmentation we find a sharply marked contrast between the formative and nutritive parts of the egg, inasmuch as the latter does not seg- ment. The terms holoUastie and mz- roblastiG therefore have been applied to total and partial seg- mentation respec- tively. Nevertheless, in total segmentation also,
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. FIG. 104.—Unequal segmentation of the Frog's tgg (after Eckeij in ten succe^ve stages. and larger portion, in which the segmentation proceeds much more slowly than in the former. In partial segmentation we find a sharply marked contrast between the formative and nutritive parts of the egg, inasmuch as the latter does not seg- ment. The terms holoUastie and mz- roblastiG therefore have been applied to total and partial seg- mentation respec- tively. Nevertheless, in total segmentation also, either groups of segments of a definite quality, or, at any rate, a fluid yolk material may be Used FIG. 105. Segmentation of the germinal di&c of a Fc vd's egg, for the nourishment ^face view (after Koaiker)'. ^germinal disc with the first vertical furrow ; B, the same with two vertical furrows of the developing crossing one another at right angles ; C and L>, more ad- embryo. In fact, the vanced stagos with 8ma11 ceutral sesmeuts- contents of every egg consists of two parts—(1) of a viscous albu- minous protoplasm; and (2) of a fatty granular matter, the deutoplasm, or food yolk. The first is derived from the protoplasm. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. London, Swan Sonnenschein & co.
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