Heteroplastic Transplantation of Halves of Girdle Rudiment in Amblystoma.

In heteroplastic transplantations of the eye, Harrison 1 found that when the lens came from the donor species and the retina from the host species, each part exerted an influence on the other's growth. In order to see if a mosaic system would react in a similar way when the rudiment contained tissue from the two species, halves of the girdle rudiment were transplanted between Amblystoma punctatum and A. tigrinum. Reciprocal transplants of dorsal, ventral, anterior and posterior halves of the girdle rudiment were made. Except in a few cases killed for the study of intermediate stages, all animals were raised until the tigrinum of the pair had a fully formed fourth digit, usually 70 to 80 days after operation.

The limbs and girdles, both normal and operated, were prepared by a modified van Wihje method for the staining of cartilage, and after the muscles had been carefully removed, were mounted in damar. It was found that at 80 days there are well marked differences between the normal girdles of the two species. The punctatum girdle is smaller, has undergone considerably more chrondrification than that of the tigrinum, has a rounded coracoid and a short, stout scapula which passes gradually into the broader suprascapula. The tigrinum girdle is larger, having its coracoid shaped more like a plow, and having a very long, slender scapula at the top of which is a much broader suprascapula.

The specificity of the transplanted tissue was shown by the fact that there was no regulation of form due to transplantation into the girdle region of the host species. The portion of the operated girdle that had come from the donor could easily be recognized. The procoracoid and the muscles attached to the operated girdles were so variable that they could not be studied.