[Evolution of the jorphogenetic capacity of the stomodeal area inPleurodeles waltlii Michah. Study by intrablastocelic transplantation and in vitro culture].

Transplantations into the blastocoel of gastrulae and cultures in vitro of the stomodeal region ofPleurodeles waltlii Michah embryos have been carried out. These experiments gave the following results:Neural crest cells reach the stomodeal region at the young tail-bud stage (stage 22), and are able to take part in formation of teeth and cartilage, it is possible to dissociate the phenomena of mouth opening, complete mouth formation and complete head formation, differentiation of a digestive tube from the pharyngeal endoderm and the formation of a mouth opening both depend on the presence of mesentoderm and mesectoderm in the explant or in the environment, during the tail-bud stage a symmetry factor plays a part in mouth formation, bone formation likewise coincides with the presence of neural crest cells.