| Description | Weldon writes: 'In the early part of this year I was enabled, by the courtesy of the Royal Society, to examine some specimens of Bdellostoma Forsteri, collected by Mr Sedgwick by means of a grant from the Society. As a result of this examination, it appeared that the head kidney, described by Johannes Muller as connected, on the one hand with the segmental duct, and on the other by means of a branch of segmental tubules with the pericardium, had become modified in a very peculiar manner. The connexion with the Segmental duct, and the one or two glomeruli (both shown by Wilhelm Müller to exist in the embryo of Myxine) had disappeared, all that remained being a plexus of tubules, opening into the pericardium, but without any other opening whatever, and entirely unconnected with the rest of the kidney. This plexus was closely surrounded by a network of blood-vessels, and the larger tubules contained altered blood-corpuscles. In seeking for a parallel, among other Vertebrates, to this peculiar modification of a portion of the kidney, I was struck by the following facts:— In Teleostei and Ganoids, Balfour has shown that the head kidney is often replaced, in the adult, by a mass of lymphatic tissue, richly supplied with vessels. Emery has studied the development of this tissue; he finds in the embryo of many Teleostei, at an early stage, a single pronephric funnel, communicating with the segmental duct; the rest of the “intermediate cell-mass,” being an undifferentiated blastema surrounding the duct. In later development, only a portion of this tissue becomes converted into renal tubules; the rest remaining through life as “lymphatic” tissue, richly supplied with vessels.'
Annotations in pencil and ink.
Subject: Zoology / Physiology
Received 30 October 1884. Read 27 November 1884. Communicated by Michael Foster.
A version of this paper was published in volume 37 of the Proceedings of the Royal Society as 'Note on the origin of the suprarenal bodies of vertebrates'. |