Experimental Production of Atrophied and Partly De- Ficient Limbs (phocomelias) in the Axolotl Embryo*

The many different types and variations of deformities of limbs in animals and man are usually described and grouped from the morphological or genetical point of view. A very few biological experiments have been done for the purpose of elucidating the causes which produce special types of deformities in the embryo. In an earlier paper (Brandt, 1940) the author has shown that supernumerary limbs such as reduplications and some higher degrees of multiplications can be produced experimentally in the frog embryo by special methods. Contrasting with the group of supernumerary limbs is the group showing stunted growth or even absence of the limb as a whole. On the other hand, there may be absence of parts of a single limb such as phocomelias and stunted growth or abnormal position of the digits. The following experiments are the first which have been published concerning the problem of experimental production of various types of atrophied limbs in the amphibian embryo.