132 Ss. R. DETWILER 
a dissecting microscope. The general behavior of the limbs in 
response to externally applied stimuli could thus be carefully 
studied. The most successful method of studying the behavior 
of the limbs in response to applied tactile stimulation consisted 
in inhibiting total swimming movements which so character- 
istically dominate the action system at this period, by placing 
the animal in very shallow water. By so doing, swimming move- 
ments could be performed only with considerable difficulty, 
resulting thereby in an increased effort on the part of the animal 
to progress solely by means of its limbs. 
The first appearance of reflexes in the transplanted limbs of 
seres ASI did not appear until about two days after the first 
appearance of those in the normal intact limb, which were first 
noticed about fourteen days after the operation. This slight 
delay is probably an index of the period required for reorgani- 
zation and readjustment of the limb rudiment subsequent to 
its reimplantation. 
The time after the operation when the normal limb reflexes 
first appear cannot adequately be stated in terms of days, owing 
to the fact that the various factors which determine the rate of 
growth were not entirely controlled. In general, however, it can 
be stated that normal limb reflexes begin at a period when the 
third digit makes its first appearance. At this time the yolk 
is almost, if not entirely, absorbed and the larva begins to feed. 
A description of the normal development of the external features 
of the limb up to this period has been given by Harrison (18, 
page 417). 
Of the series ASI, case 12, preserved sixty-four days after the 
operation, was sectioned and studied. The transplanted limb 
is innervated by a plexus composed of the normal segmental 
nerve components (table 2) and the intrinsic nerve distribution 
within the limb is practically identical with that in the normal 
limb. No shoulder muscles of the group which typically develop 
in the heterotopic position (table 3) were lacking and all received 
peripheral innervation. The shoulder-girdle was somewhat 
atypical. The coracoid was rather short, the procoracoid and 
scapula were abnormally thick and the more dorsal portion of 
