Fate of blastopore birds5/27/2023 It consists of a thicker central mass of cells with lateral wings the central part, or primordium of the notochord, is continuous posteriorly with the axis of the primitive streak (Fig. Two stages of the head-process are shown in tranverse section a short distance in front of the primitive knot in Figs. 40 C, between A-A and B-B more highly magnified. 41.âThe part of the section shown in Fig. The primitive groove must be regarded as an expression of the forces of invagination of the mesoblast, and the primitive folds as the lips of this invagination.'â - '^^â¢-â ff* « oC Q ©⢠Fig. This part of the mesoblast is homologous with the mesoblast of the ventral lip of the blastopore of reptiles and amphibia, and, like it, is the first place of formation of blood. The mesoblast thus extends into the opaque area behind the embryo at a very early stage (Figs. The mesoblast grows out, not only from the sides of the head-process and primitive streak, but also from the hind end of the latter, that is from the primitive plate. 80 THE DEVELOPMENT OF THE CHICK the latter which corresponds to the future vascular area. The development of the chick an introduction to embryology. This image could have imperfections as it’s either historical or reportage. Alamy charges you a fee for access to the high resolution copy of the image. This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright.
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