. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. HOLOBLASTIC A-XD MEKOBLASTIC SLOMEXTATION. Ill the upper pole than the lower, and marks the line of division between the upper and smaller portion of the egg from the lower. m m Fig. 104.—Unequal stguieuuitioa of the Frog'a tgg (after Kckei; lu teu succesbiVe sUges. and larger portioii, in which the segmentation pioceeils 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
. Elementary text-book of zoology, general part and special part: protozoa to insecta. Animals. HOLOBLASTIC A-XD MEKOBLASTIC SLOMEXTATION. Ill the upper pole than the lower, and marks the line of division between the upper and smaller portion of the egg from the lower. m m Fig. 104.—Unequal stguieuuitioa of the Frog'a tgg (after Kckei; lu teu succesbiVe sUges. and larger portioii, in which the segmentation pioceeils 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 holohlastie and ms- rohlastlc 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. Segmeutation of the gormiual disc of a '; f ere-, surface view (after Kolliker). A, germinal disc with the first vertical furrow ; B, the same with two vertical furrows crossing one another at right angles; C and X>, inure ad- , T c i_ , 1 vanced sta^'cs with small central segments. embryo. In fact, the contents of every egg consists of two parts—(1) of a viscous albu- minous protoplasm; and (2) of a fatty granular matter, the lasm, 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; Metcalf Collection (North Carolina State University). NCRS. London, Swan Sonnenschein
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanimals, bookyear1892
