The structure and development of what I have called the interrenal body in Elasmobranchii so closely correspond with that of the mesoblastic part of the suprarenal bodies of the Reptilia, that I have very little hesitation in regarding them as homologous[241]; while the paired bodies in Elasmobranchii, derived from the sympathetic ganglia, clearly correspond with the part of the suprarenals of Reptilia having a similar origin; although the anterior parts of the paired suprarenal bodies of Fishes have clearly become aborted in the higher types.
In Elasmobranch Fishes we thus have (1) a series of paired bodies, derived from the sympathetic ganglia, and (2) an unpaired body of mesoblastic origin. In the Amniota these bodies unite to form the compound suprarenal bodies, the two constituents of which remain, however, distinct in their development. The mesoblastic constituent appears to form the cortical part of the adult suprarenal body, and the nervous constituent the medullary part.
Bibliography of the Suprarenal bodies.
(503) M. Braun. “Bau u. Entwick. d. Nebennieren bei Reptilien.” Arbeit. a. d. zool.-zoot. Institut Würzburg, Vol. V. 1879.
(504) A. v. Brunn. “Ein Beitrag z. Kenntniss d. feinern Baues u. d. Entwick. d. Nebennieren.” Archiv f. mikr. Anat., Vol. VIII. 1872.
(505) Fr. Leydig. Untersuch. üb. Fische u. Reptilien. Berlin, 1853.
(506) Fr. Leydig. Rochen u. Haie. Leipzig, 1852.
Vide also F. M. Balfour (No. [292]), Kölliker (No. [298]), Remak (No. [302]), etc.
[219] For a full account of these structures the reader is referred to T. W. Bridge, “Pori Abdominales of Vertebrata.” Journal of Anat. and Physiol., Vol. XIV., 1879.
[220] Kölliker’s account of this septum, which he calls the mesocardium laterale (No. [298], p. 295), would seem to imply that in Mammals it is completed posteriorly even before the formation of the liver. I doubt whether this takes place quite so early as he implies, but have not yet determined its exact period by my own observations.
[221] “Connective and vasifactive tissues of the Leech.” Quart. J. of Micr. Science, Vol. XX. 1880.
[222] Vide Gegenbaur, “Zur vergleich. Anat. d. Herzens.” Jenaische Zeit., Vol. II. 1866, and for recent important observations, J. E. V. Boas, “Ueb. Herz u. Arterienbogen bei Ceratoden u. Protopterus,” and “Ueber d. Conus arter. b. Butirinus, etc.,” Morphol. Jahrb., Vol. VI. 1880.
[223] Boas holds that the longitudinal septum is formed by the coalescence of a row of longitudinal valves, but this is opposed to Lankester’s statements, “On the hearts of Ceratodus, Protopterus and Chimæra, etc.” Zool. Trans. Vol. X. 1879.
[224] For a good description of the adult heart vide Huxley, Article “Amphibia,” in the Encyclopædia Britannica.