The practice of obstetrics, designed for the use of students and practitioners of medicine . dg. ^?^%sj Fig. 59.—Formation of Gastrula, Amphiox-us. The entoderm, en., has begun to in-vaginate, making the segmentation cavity,, smaller; , ectoderm.—{After Hat-schek.). ^yoo] Fig. 60.—Formation of Gastrula in Am-PHioxus. The segmentation cavity hasalmost disappeared between the ecto-derm, ec, and the invaginated entoderm,en., which lines the digestive cavity, ,or enteron. The opening of the latter isthe original oral opening or blastopore, A single mesodermic cell, , atthe left a
The practice of obstetrics, designed for the use of students and practitioners of medicine . dg. ^?^%sj Fig. 59.—Formation of Gastrula, Amphiox-us. The entoderm, en., has begun to in-vaginate, making the segmentation cavity,, smaller; , ectoderm.—{After Hat-schek.). ^yoo] Fig. 60.—Formation of Gastrula in Am-PHioxus. The segmentation cavity hasalmost disappeared between the ecto-derm, ec, and the invaginated entoderm,en., which lines the digestive cavity, ,or enteron. The opening of the latter isthe original oral opening or blastopore, A single mesodermic cell, , atthe left at the union of the ectodermand entoderm.—{After Hatschek.) According to this hypothesis, Mono-tremes and Marsupials are the connect-ing links between birds and the evolution of viviparous mammals the membranes which were formerly of service in development within egg capsulesand in the presence of nutritive yolk now become adapted for intra-uterine devel-opment where nourishment is received direct from the maternal organism. Insome of the forms observed, the cells of the morula are not uniform in appear-ance, larger clear cells being massed at one pole, smaller dark cells at the clearer cells grow and divide more rapidly, finally forming a c
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectobstetrics, bookyear1
