148 S. R. DETWILER 
of the third somite to the posterior border of the fifth, centering 
ventral to the fourth somite. In the series HS3 the additional 
rudiment centered ventral to the seventh somite and its anterior 
border was contiguous with the posterior border of the normal 
intact limb rudiment. In these experiments the two limb buds 
always began independent growth; but in seven cases out of 
nine positive experiments, the posterior rudiment sooner or 
later reduplicated so that its anterior or disharmonic member 
fused with the normal limb to form a fused double limb. The 
posterior (harmonic) member which remained as a free limb 
functioned in all cases, but there was only one case, however, 
in which it functioned perfectly. Both of the two cases in which 
a single limb developed exhibited normal function. The results 
of this series of experiments are seen in table 1b. 
Series HS4. In this series of experiments, the additional 
anterior limb centered ventral to the eighth somite, so that the 
anterior margin of the transplanted limb bud was separated 
from the intact bud by the distance of one segment. In twenty- 
one positive experiments only eight developed normal limbs, 
the remainder forming reduplicated appendages. All of the 
reduplications functioned very imperfectly, as did also seven 
of the single limbs. In no case did function consist of more 
than slight flexion and extension of the forearm; yet in others 
motion was entirely restricted to twitchings of the hand. 
The complete absence of cases with perfect function is in 
striking contrast with the 41 per cent which exhibited perfect 
function of the autoplastic series AS4, in which case the anterior 
limbs were transplanted to the same relative position (compare 
table La, series AS4, with table 1b, series HS4). 
Series HS5. In the series HS5 the transplanted limb centered 
ventral to the ninth segment. The results of these experiments 
are seen in table 1b. In twenty-five positive experiments 
eleven developed normal limbs, eight of which showed very 
imperfect function. Of the fourteen cases which reduplicated, 
only five exhibited any function. This consisted mostly of slight 
twitchings in the hand and in several cases shght movements 
of the forearm. The same was also true of the normal limbs. 
