SYMMETRY IN TRANSPLANTED LIMBS 95 
Likewise, the well-known experiments of Tornier ('05) upon 
tadpoles of Pelobates, in which the hind-lmib bud was divided 
in an early stage, some of the cases of Lissitzky CIO), and Delia 
Valle's case of reversed regeneration conform closely to Bate- 
son's rules. Although the end results of the experiments of Tor- 
nier and of Delia Valle are analogous, there is, however a sharp 
difference of opinion regarding the exact mode of origin of Tor- 
nier's double supernumerary hind legs, Tornier maintaining that 
they both arise from the dorsal part of the pelvis, which was 
split off by the operation, while Delia Valle holds them to be 
analogous to his own case. 
Delia Valle has laid particular stress upon the supposed identity 
of change of asymmetry and reversal of polarity, and has sought 
to make the various cases of superregeneration which have been 
reported fit into his scheme of 'doppia rigenerazione in versa.' 
The case on which Delia Valle bases his discussion of these ques- 
tions is that of a newt (Triton) in which the left anterior limb was 
fractured in the region of the brachium and cicatrization pre- 
vented by tying a silk thread around the limb at that level. 
Twentj^ days later the same limb was amputated a short distance 
below the point of fracture. There regenerated three perfect 
limbs, one from the distal end of the stump and two from the 
region of the fracture. Of the latter, one was from the proximal 
end of the small portion beyond the ligature and the other was 
apparently a continuation of the stump proximal to the fracture. 
The first and last of the three were left limbs, i.e., of the same side 
as the original, while the one which regenerated in a distoproxi- 
mal direction was reversed. The end result was a triple append- 
age in which the three members were placed in accordance with 
Bateson's rule. 
Delia Valle seeks to make the cases of Tornier ('05) and Lis- 
sitzky ('10) conform to this scheme, and falls into line with 
Przibram ('09) who had previously given a schematic represen- 
tation of the same phenomena, which he termed 'Bruchdreifach- 
bilding.' He also interprets in the same way the reduplications 
obtained by Braus ('04, '09) and myself ('07) in the transplanta- 
tion of embrj^onic limb buds. He suggests that when the limb 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 32, NO. 1 
