[322] I may state that my determinations of the arrangement of the circulation were made by actual observation of the flow of the blood under the microscope.
[323] My figure may be compared with that of Leydig, Rochen und Haie, Plate III. fig. 6. Leydig calls the arterial ring the sinus terminalis, and appears to regard it as venous, but his description is so short that this point is not quite clear.
[324] Rochen und Haie and Untersuchung. ü. Fische u. Reptilien.
[325] I do not feel sure that Leydig's unpaired suprarenal body is really my interrenal body, or at any rate it alone. The point could no doubt easily be settled with fresh specimens, but these I unfortunately cannot at present obtain. My doubts rest partly on the fact that, in addition to my interrenal body, other peculiar masses of tissue (which may be called lymphoid in lieu of a better name) are certainly present around some of the larger vessels of the kidneys which are not identical in structure and development with my interrenal body, and partly that Stannius' statements (to be alluded to directly) rather indicate the existence of a second unpaired body in connection with the kidneys, though I do not fully understand his descriptions.
[326] Fische u. Reptilien, p. 14.
[327] Rochen u. Haie, p. 18.
[328] Vergleichende Anatomie, II. Auflage.
[329] Stannius' description is not quite intelligible, but appears to point to the existence of a third kind of body connected with the kidney. From my own observations (vide above), I am inclined to regard it as probable that such a third body exists.
[330] “Urogenitalsystem d. Plagiostomen.” Arb. zool.-zoot. Inst. z. Würzburg, Vol. II.
[331] There is a very good figure of them in Semper's paper, Pl. XXI. fig. 3.