Abstract
The microscopical examination of the first haploid salamander to live through metamorphosis shows that the transformation to a terrestrial vertebrate was normal and practically completed at the time of its death. All the organs and structures that develop shortly before and during metamorphosis and are typical for the adult salamander, e.g., the integument, the pharyngeal derivatives, and various glands of special function, are present.The nuclei in all organs and tissues of the haploid animal are smaller than normal. This is indirect evidence of the uniformly haploid condition of the animal. The majority of the organs are smaller than in the control but contain a larger number of cells. In some glands, the reduced cell size has been completely compensated by the increase in cell number.