[37] For this specimen I am indebted to Dr Günther.
[38] According to Müller (Myxinoiden, 1845) there is in Myxine an abdominal pore with two short canals leading into it, and Vogt and Pappenheim (An. Sci. Nat. Part IV. Vol. XI.) state that in Petromyzon there are two such pores, each connected with a short canal.
[39] My own rough examination of preserved specimens was hardly sufficient to enable me to determine for certain the presence or absence of these pores. Mr Bridge, of Trinity College, has, however, since then commenced a series of investigations on this point, and informs me that these pores are certainly absent in Scyllium as well as in other genera.
[40] The description of the attachment of the vas deferens to the testis in the Carp given by Vogt and Pappenheim (Ann. Scien. Nat. 1859) does not agree with what I found in the Perch (Perca fluvialis). The walls of the duct are in the Perch continuous with the investment of the testis, and the gland of the testis occupies, as it were, the greater part of the duct; there is, however, a distinct cavity corresponding to what Vogt and P. call the duct, near the border of attachment of the testis into which the seminal tubules open. I could find at the posterior end of the testis no central cavity which could be distinguished from the cavity of this duct.
[41] This is mentioned by Müller (Ganoid fishes, Berlin Akad. 1844), Hyrtl (loc. cit.), and Günther (loc. cit.), and through the courtesy of Dr Günther I have had an opportunity of confirming the fact of the presence of the abdominal pores on two specimens of Lepidosteus in the British Museum.
[42] My account of the development of these parts in Amphibians is derived for the most part from Götte, Die Entwicklungsgeschichte der Unke.
[43] It is called Kopfniere (head-kidney), or Urniere (primitive kidney), by German authors. Leydig correctly looks upon it as together with the permanent kidney constituting the Urniere of Amphibians. The term Urniere is one which has arisen in my opinion from a misconception; but certainly the Kopfniere has no greater right to the appellation than the remainder of the kidney.
[44] In Bombinator igneus, Von Wittich stated that the embryonic condition was retained. Leydig, Anatom. d. Amphib. u. Reptilien, shewed that this is not the case, but that in the male the Müllerian duct is very small, though distinct.
[45] This account of the origin of the Wolffian body differs from that given by Waldeyer, and by Dr Foster and myself (Elements of Embryology, Foster and Balfour), but I have been led to alter my view from an inspection of Mr Sedgwick's preparations, and I hope to shew that theoretical considerations lead to the expectation that the Wolffian body would develop independently of the duct.
[46] The right oviduct atrophies in birds, and the left alone persists in the adult.