. Principles of zoölogy : touching the structure, development, distribution, and natural arrangement of the races of animals, living and extinct with numerous illustrations : Part 1, Comparative physiology : for the use of schools and colleges. Fig. 114. Fig. 115. Fig. 116. is formed npon it, (Fig. 114.) This depression becomes bydegrees a deep furrow, and soon after a second furrow ap-pears at right angles with the former, so that the germ nowpresents four elevations, (Fig. 115.) The subdivision goeson in this way, during the second and third days, until thegerm is divided into numerous littl
. Principles of zoölogy : touching the structure, development, distribution, and natural arrangement of the races of animals, living and extinct with numerous illustrations : Part 1, Comparative physiology : for the use of schools and colleges. Fig. 114. Fig. 115. Fig. 116. is formed npon it, (Fig. 114.) This depression becomes bydegrees a deep furrow, and soon after a second furrow ap-pears at right angles with the former, so that the germ nowpresents four elevations, (Fig. 115.) The subdivision goeson in this way, during the second and third days, until thegerm is divided into numerous little spheres, giving the sur-face the appearance of a mulberry, (Fig. 116.) This ap-pearance, however, does not long continue ; at the end ofthe third day, the fissures again disappear, and leave novisible traces. After this, the germ continues to extendas an envelop around the yolk, which it at last entirelyencloses. 309. On the tenth day, the first outlines of the embryobegin to appear, and we soon distinguish in it a depressionbetween two little ridges, whose edges constantly approach.
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectp, booksubjectzoology
