. Text-book of embryology. Embryology. coe Fig. 28.—Two methods of formation of the T, in Tubularia mesem- bryanthemum. (After Brauer.) A, egg segmenting in normal method. B, egg segmenting in abnormal Fig. 29. —Formation of endoderm in Tubularia mesembryanthemum. (After Brauer.) A, budding of endoderm cells from blastula wall. B, morula stage, coe, spaces which will iiltimately form the coelenteron; ect, ectoderm ; md, endoderm ; inst, interstitial cells. the assumption that this is the case with the blastulae of Tubularia also. In any case a solid morula stage is soon reach
. Text-book of embryology. Embryology. coe Fig. 28.—Two methods of formation of the T, in Tubularia mesem- bryanthemum. (After Brauer.) A, egg segmenting in normal method. B, egg segmenting in abnormal Fig. 29. —Formation of endoderm in Tubularia mesembryanthemum. (After Brauer.) A, budding of endoderm cells from blastula wall. B, morula stage, coe, spaces which will iiltimately form the coelenteron; ect, ectoderm ; md, endoderm ; inst, interstitial cells. the assumption that this is the case with the blastulae of Tubularia also. In any case a solid morula stage is soon reached in which the whole interior of the blastula becomes clogged up with a mass of cells. This mass of cells constitutes the rudiment of the endoderm of the adult, whilst the original blastula wall forms the ectoderm. In the solid mass of endoderm spaces begin to appear owing to the absorp- tion of some of the central cells. These spaces (coe, Fig. 29) eventually coalesce so as to form one cavity which is the gastral cavity or coelenteron of the adult. The embryo has now the form of a circular disc, and from its edges a series of blunt protuberances grow out. These are the rudiments of the aboral tentacles of the adult: they are bent towards the future aboral end of the body. At. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
Size: 2141px × 1167px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
