130 S. R. DETWILER 
taken, and at distances ranging from one to seven segments 
posterior to the normal situation. These experiments consti- 
tute the autoplastic transplantations. 
In other experiments the normal anterior limb was left intact 
and additional right anterior limb rudiments from other embryos 
were implanted respectively the distance of three, four, and 
five segments posterior to the normal intact limb rudiment of 
the host. These latter experiments constitute the homoplastic 
transplantations. 
The larvae were preserved in sublimate-acetic fixing fluid at 
intervals from thirty to eighty days after the operation, the major- 
ity being under observation for about sixty days. A study of 
the animals was made from transverse sections cut 10u in thick- 
ness and stained with Ehrlich’s haematoxylin and erythrosin. 
A. Autoplastic transplantations 
Series AS1. In this series of experiments the limb rudiment 
was excised and reimplanted the distance of one body segment 
posterior to its normal position so that the rudiment, instead 
of centering ventral to the fourth somite as it does in the normal 
condition, now centers ventral to the fifth somite (fig. 4). The 
results of this series of experiments are presented in table 1, 
series ASI. By examination of this table it is seen that 95 per 
cent of limb rudiments so placed developed into normal limbs, 
there being only one case in twenty positive experiments in which 
the rudiment developed into a reduplicated appendage. 
The criteria used in establishing the category ‘normal limbs’ 
were based purely upon superficial conditions, the limb being 
classed as ‘normal’ only when a brachium, antibrachium, and a 
manus with the proper number of digits were developed. 
It is also seen (table 1) that 95 per cent of the limbs so trans- 
planted functioned perfectly, the movements being adaptive and 
well codrdinated with those of the opposite intact limb. 
The criteria employed in establishing the category ‘perfect 
function’ were: 1) movements of the arm on the shoulder, viz., 
flexion, extension, abduction, adduction, rotation, and circum- 
