266 ORIGIN OF AMPHIBIAN PIGMENT 



RECOED OF HOMOPLASTIC TEANSPLANTATIONS 



HETEROPLASTIC NEURAL CREST TRANSPLANTATIONS 



If Amblystoma punctatim and A. tlgrlnum larvae of stages #25 to #28 are available, 

 heteroplastic transplantations resulting In varied pigment patterns should he attempted. 

 If the white axolotl is available, the results are even more graphic. (See section on 

 "Transplantations" to determine the viable combinations.) When Urodeles of different 

 developmental rates are used, this factor must be considered. In general, the graft tis- 

 sue should be from a donor slightly older than the host. Heteroplastic transplantations 

 are best made to the normal site, transferring dorsal ectoderm and ganglion crest, along 

 with some of the nerve cord, to insure presence of crest. 



Some suggested combinations: 



Amblystoma tlgrlnum crest stage #2k to A. punctatum stage #25- 

 Amblystoma punctatum crest stage #28 to A. tlgrlnum stage #25- 



The treinspiant should be treated as in the homoplastic experiments, the operation 

 being carried out in Urodele Operating Medium and after the graft has taken, transfer the 

 host to Urodele Growing Medium for further development. 



