An introduction to the study of embryology / by Alfred C. Haddon.

  • Alfred Cort Haddon
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to the study of embryology / by Alfred C. Haddon. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    blastema, together with the general similarity of the development of the renal tubules and the identity of their adult structure, proves that the metanephros is merely a special portion of the primitive Wolffian body, which develops late. The acquisition by the posterior portion of the Wolffian body in some Elasmobranchs and Amphibia of efferent ducts opening into A Flo. 178.—Development of Metakephhos in the Fowl. [Adapted from Sedywick.] A. Transverse section through an embryo at the end of the fourth day. B. Longi- tudinal vertical section through an embryo of about the same age, showing the absolute continuity of the kidney blastema with the hindermost part of the WolflBan blastema, in which the development of Wolffian tubules is taking place. C. Trans- verse section through an embryo at the end of the sixth day. no. dorsal aorta: b.c. body-cavity; c.v. cardinal vein; k.b. kidney blastema; k.t. kidney tubule ; M.d. Mtillerian duct; mes. mesentery; vch. notochord; pe peri- toneum ; T. testis; v. ureter; v.c. vertebral centrum; W.B. Woltfian body; Wd. Wolffian duct; WtA primary, and Wt.2 secondary. Wolffian tubule. the urogenital sinus or into the extreme posterior end of the Wolffian duct, is, as Balfour pointed out, a definite step towards the formation of a metanephros. According to Mikalovics, the mesonephros remains functional till the second year in Lizards, and thus is functional at the same time as the metanephors.
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