[Histochemical data on the first stages of the fore and hind limb development inPleurodeles waltlii Michah. (Urodela, amphibia)].

Localization of 4 dephosphorylating enzymes (alkaline phosphomonoesterase, acid phosphomonoesterase, nonspecific ATP-ase, and AMP-ase=5' nucleotidase) has been studied in both constituants of the fore- and hind limb buds inPleurodeles waltlii Michah. during the first stages of development.There is no specific enzymatic reaction in the bud epiderm; the negative or positive results concerning the four enzyme groups are observed in the whole epiderm of the larval body and not only in the limb bud epiderm: the epiderm is devoid of the alkaline phosphomonoesterases which hydrolyze sodiumβ-glycerophosphate and sodiumα-naphthyl phosphate, and of AMP-ase and acid sodiumβ-glycerophosphatase; it is rich in ATP-ase and acid naphthol AS/BI phosphatase). The enzymatic reactions studied are present in the limb bud mesoderm, with the exception of the acidβ-glycerophosphatasic one. At the level of the basement membrane, only in the fore and hind limb buds, the reaction for alkalineβ-glycerophosphatase is positive.