. Key to North American birds. Containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland and Lower California, with which are incorporated General ornithology: an outline of the structure and classification of birds; and Field ornithology, a manual of collecting, preparing, and preserving birds . » .r^.^^x^:^^^^^ i25«SS 1 lilillilliillBiilli 11 1 \;h . ~~^^^#rt in. Fig. 112. —Further development of liens egg; after Haeckel:A, the mulberry mass of cleavage cells, h. same as
. Key to North American birds. Containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland and Lower California, with which are incorporated General ornithology: an outline of the structure and classification of birds; and Field ornithology, a manual of collecting, preparing, and preserving birds . » .r^.^^x^:^^^^^ i25«SS 1 lilillilliillBiilli 11 1 \;h . ~~^^^#rt in. Fig. 112. —Further development of liens egg; after Haeckel:A, the mulberry mass of cleavage cells, h. same as seen on top infig. Ill, F, here viewed in profile in section, resting upon », thesimply-shaded part of the figure, to represent conventionally themass of food-yelk. A, morula stage (as before); B. hlastulastage, the mass of cells, 6, forming the blastoderm, uplifted fromthe food-yelk, leaving the cleavage-cavity. s\ w, the thickenedrim of the germ-disc; C, the blastula in process of inversion, bywhich a layer of entoderm-cells, t, growing from periphery tolayered; the rising of the inner layer centre, will apply itself to the layer of , obliterat-to meet the outer results in a cavitv ™^ ^^ cleavage-cavity, s; D, the disc-gastrula completed, by J union of entoderm, (, with exoderm, e, leaving the primitivebetween itself and the food-yelk, D, d. intestinal cavity, il. which is quite similar in appearance to theThis cavity exactly resembles the cleavage cavity
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1896
