O. Gy. Dely szerk.: Vertebrata Hungarica 23. (Budapest, 1989)
Stohl, G.: Some remarks of the paired ovaries of birds (Aves) 29-32. o.
ever, what is more remarkable is that, just as in other birds, there is only one functional widuct, the left one, available for the transport of eggs. The right oviduct of the kiwi is also rudimentary. Among the other birds having paired ovaries as an exceptional trait only some cases have been reported of eggs producing paired ovaries. WHITE (1969) found in a female Peregrine obtained from Alaska not only paired ovaries, from which the left was markedly atrophied, but the right ovary had 5 enlarged follicles about 25 mm in diameter and two visible ovarian scars from which follicles had ruptured. In hybrid females originating from parents belonging to different species or genera paired ovaries have several times been found, but in every case only one oviduct: the one on the left side. In 1835 EYTON stated the presence of paired ovaries in a genus-hybrid hen Lyrurus tetrix x Phasianus colchicus . But sometimes the ontogeny of the reproductive organs can be distorted in interspecific hybrids; YAMASHINA (1940) found in a female Lonchura domestica x Lonchura malaccá atricapilla paired ovaries, but they had a quite different appearance than the normally developed, left-side ovaries from reproductive fertile female birds. Their surface was almost smooth and therefore they looked very like the paired testes of male birds. The only existing difference was that the paired "ovaries" were more flattened than the testes. It was without doubt that these abnormally developed organs cannot be regarded simply as symmetrically located doubled ovaries, and therefore some of the authors called them intersex-organs. Until the end of the 19 60s it was assumed by most of the authors that these paired ovaries showing many similar features with the sexually undifferentiated primary "anlagen" of the gonads are brought about by the genetic discrepancies originating from the different genomes of the parental species. Paired intersex-organs have quite unexpectedly been found in two female genus-hybrids originating from a crossbred-experiment between Muskovy drakes ( Cairina moschata Phillips, 1822) and domesticated female ducks ( Anas platyrhyncho s Linnaeus, 1758). The crossbreeding experiment has been carried out at the farm of the Chair of Animal Husbandry of the University for Agriculture (Gödöllő, Hungary) with the aim to obtain heterotic genus-hybrids. The crossing experiments begun in the early 19 50s and were later continued at the farm of the Laboratory for Animal Genetics of the Hungarian Academy of Sciences (Gödöllő, Hungary) (STOHL 19 70). In the crossing experiments performed till 19 58 the obtained sex-proportions were about four males to one female genus-hybrid. All of the crossbred females were sterile, they had only a quite rudimentary left ovary weighing about 100 mg (!) and a left oviduct, also rudimentary, of about 190-200 mg. In an other series of crossbreeding experiments, which was performed in the years 1958- 1960, the result was somewhat different. Obtained were 32 crossbred ducks, but only two of them were females, all of the others drakes. Whereas formerly no mating between the genus-hybrid ducks could be observed, in the above-mentioned series the hybrid drakes often tried to mate the two females - of course all of the pairings were sterile. In the first months of 1962 all hybrids from this series had been dissected and their organs prepared. Instead of a rudimentary left ovary and a similarly reduced left oviduct both of these hybrid females had paired gonads at the normal place of the testes, but they had only one oviduct on the left side. The genus-hybrid duck. No. 59/62 originated from a Muskovy drake (No. 545/42) and a Hungarian White duck (No. 567/28), she hatched June 9 th , 1959. She had dark brown-coloured plumages with grayish scales on the belly. The other genus-hybrid duck, No. 60/37 was the offspring of the above-mentioned Muskovy drake (No. 545/42) and a crossbred domesticated duck. No. 61 (Khaki Campbell Ô, No. 579/72 x Hungarian White <j). No. 569/35). She had a metallic greenish-blackish plumage with white feather tips, her plumage had whitish spots on the belly and in the circumanal region. She hatched September 21 st , 1960. For body- and organ-weights of the two genus-hybrid females see Table 1. PLATE I. Some organs of the adult female intergeneric hybrid No. 59/62 (Muskovy drake x domesticated duck). - Left, above: Syrinx characteristic for ducks. - Left, at the bottom: 5 yolks from the abdominal cavity; the largest of them immediately after detachment from the ovary. - Middle: The paired ovaries. - Right: Fully (normally) developed left oviduct. (All figures of natural size)
