TRANSPLANTATION OF LIMBS IN AMBLYSTOMA 



123 



Series A 



In the first series of experiments (twent}' in number) the limb 

 bud was excised and reimplanted the distance of two segments 

 anterior to the normal position. In preparing the wound for the 



Fig. 1 Drawing of Amblystoma embryo in the tail-bud stage (stage 29). 

 The circle ventral to the pronephros (PA'') indicates the position of the fore-limb 

 rudiment. MY3, third myotome; MYl, first myotome; GSS, third external gill 

 swelling. X 10. 



Fig. 2 Drawing of Amblystoma embryo, showing the fore-limb rudiment 

 transplanted the distance of two segments anterior to its normal position (cf. 

 fig. 1). The ectoderm and mesoderm of the third gill swelling was removed prior 

 to reimplantation of the limb. MYl, myotome 1; GSl, first gill swelling. X 10. 



Fig. 3 Drawing of Amblystoma embryo following excision of the ectoderm 

 and mesoderm of the gill region and the reimplantation of the right fore-limb 

 rudiment (LR) into the excavated area. Denuded limb area covered with indif- 

 ferent ectoderm. X 10. 



reception of the transplant, an area of ectoderm with the under- 

 lying mesoderm ventral to the first and second myotomes was 

 excised. This excision involved the tissues normally forming 

 the third gill (fig. 2). The excavated limb area was cleaned of 

 all free mesoderm cells, but was not covered. The results are 



