BIEDS. 347 



tlieir rise, which afterwards terminate in the ureters. The two 

 ureters run (in the male birds in close proximity to the vasa defe- 

 rentia) to the cloaca. On tlie absence of an urinary bladder we 

 have already spoken; the secretion too is here a pultaceous, white 

 mass and by no means a liquid substance as in the mammals. 

 The arteries of tlie kidneys arise principally from the aorta, but in 

 addition they derive branches from the ischiadic arteries for their 

 middle and posterior portions. The veins of the kidneys run into 

 the iliac veins. An aiferent renal vein, which Jacobson ascribes 

 to birds, is not present; it is the vena {liolumhalis, which runs 

 through the anterior part of the kidney, which has been taken for 

 it\ The succenturiate kidneys, which lie under the anterior por- 

 tion of the kidneys are of a yellow or orange colour. There seems 

 to be some relation between them and the sexual organs (ovaries, 

 testes), close to which tliey are situated; for they have been 

 observed to be much larger in the pairing season, when the sexual 

 organs are also swollen, than is usual at other times. 



Usually only one ovary and one oviduct, that of the left side, is 

 developed. In some of the birds of prey, and occasionally in other 

 birds also, two ovaries have been observed, of which, however, 

 that of the right side was much more feebly developed, whilst also 

 a right oviduct that terminated blindly and was much smaller than 

 the left, mostly without, in some cases however with a right ovary, 

 has been met with". Consequently the single ovary of birds does 



^ Compare A. Ferrein Mem. de I' Acad, des Sc, 1749, p. 489 and foil.; G. R. 

 Treviranus Beohachtungeti aus der Anat. u. Phys., istes Heft, Bremen, 1839, 4*°, 

 p. 127, Tab. XIX. fig. 117; Mueller de Glandul. secern, structura, pp. 92 — 94, Tab. 

 XIII. figs. 7, 9, 10; R. Wagner has given a figure of a Malphigian body from Strlx 

 A luco, Icones Physiol. Tab. 20, fig. 6, and Bowman from the pan-ot in his paper on 

 the kidney, Phil. Trans. 1842, Pt I. PI. IV. fig. 13. 



2 Compare, besides CuviER and Tiedemann {Zoologie, II. s. 712 — 726), Emmert in 

 Reil's Archiv, X. s. 382 ; G. Spangenberg Disquisitio anat. circa partes genitales fcemi- 

 neas avium, cum Tab. V. fen., Gottingse, 18 13, 4to (Tab. II. fig. 4 g, right oviduct in a 

 duck); Geoffrot St.-Hilaire Mem. du Mus. d'Bist. not., 1823, Tom. x. pp. 57 — 

 84, PI. IV.; R. Wagner Beitrdge zur Anat. der Vbgel, 1. 1. s. 271 — 283; (a figure of 

 the two ovaries in Falco palumbarius ; in Gypogeranus he found a right ovary with 

 right oviduct). 



There are in the chick, as Rathke has observed, originally two ovaries and two 

 oviducts. Those of the right side, however, soon cease to grow at the same rate as 

 those of the left, and are absorbed in a few weeks after the chick has left the egg. 



