DETAILS OF EARLY EMBRYO. 



89 



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Figs. 72 A E.— Transverse sections and details of the blastoderm shown in fig. 72. The sections pass anteriorward (rom 

 the region of the caudal folds, shown in section A, as far as the "neck" region of the embryo, section E. 



f(. Beeinnings of segmental duct. ""■*• Mesoderm. 



ret. Ectoderm at the point where this becomes continuous with the '/. YolL lying dee in the gut cjvily. 



mesoderm in the tail (olds ol the embryo. ' . Urogenital anlage. 

 ent. Entoderm. 



