ABSTRACT
Embryonic grafting in Triturus alpestris allows homosexual (♀-♀ and ♂-♂) and heterosexual (♀-♂ and ♀ ♂) connexions of anterior and posterior part of two different tail-bud-stage embryos. Most of the 46 chimaeric animals obtained have been shown to possess two pairs of gonads. Among homosexual chimaeras, females (♀-♀) possess four ovaries and males (♀-♂) four testes. Among heterosexual chimaeras, some animals (♂-♂) show two sterile anterior ovaries and two normal posterior testes, other heterosexual chimaeras (♂-♀) possess normal anterior testes and sometimes well-differentiated posterior ovaries. These results confirm those obtained in Pleurodeles waltlii by the same author.
Final sex differentiation of the gonads seems likely to be an effect of their reciprocal position down the longitudinal axis of the chimaera : an anterior ovary is entirely inhibited by a posterior testis, but a posterior ovary may differentiate and reach sexual maturity notwithstanding a well-developed anterior testis. These kinds of adult heterosexual chimaeras (♂-♀) can be accounted as hermaphrodites.
Statistically, the number of homosexual chimaeras ♂-♂ is significantly greater than the other homosexual ♀-♀ or heterosexual ♀-♂ and associations. This fact may be due to the total inhibition of anterior ovaries in some heterosexual chimaeras, but also, to a phenotypic sex reversal of the female part.
