510 S. R. DETWILER 
TABLE 6 
Showing the results following removal of the mesoderm within the area a-e X 38-8 
(text fig. 1) 
CONDITION OF THE GIRDLE AND THE EXTREMITY 
INDIVIDUAL AGE e 
S x F : 
Seaoulh Scapula | Procoracoid | Coracoid Humerus 
days | y 
Bxt.Gr7G720:.....| 20 present absent | absent absent absent 
Ext Gia Ome oe = te) 20) present | absent | absent absent absent 
has been formed is an expression of the potency of these cells to 
form only that for which they are determined at the time of the 
operation. ‘The rudimentary coracoid in these cases is smaller 
than that which developed from the tissue carried along with the 
limb cells in a typical limb-bud transplantation, but more cora- 
coid-forming tissue is present in the latter case. 
It is seen by referring to figure 1 that in the extirpation of the 
area a-e X 4-8 slightly more than the ventral half of the typical 
limb dise is included, yet fifteen out of twenty such cases de- 
veloped normal limbs. This high percentage of normal limbs 
from only the more dorsal portion of the rudiment affords addi- 
tional evidence of the true equipotentiality of the limb system. 
6. Removal of the ventral zone rudiment of the girdle and the 
entire limb rudiment. ‘This type of experiment consisted in the 
removal of the mesoderm within the area a-e X 3-8 (text fig. 
1). All the wounds were cleaned and covered. The part re- 
moved included not only the limb mesoderm, but the rudiments 
of all parts of the girdle except the suprascapula. The results 
of these experiments are shown in figures 13 and 380 and in table 6. 
The development in these cases of the suprascapula in the ab- 
sence of the limb and all other parts of the girdle lends additional 
evidence of the independence of this element in its development, 
and shows further that it develops from a separate rudiment 
(Exp. Al, A2, and tables 1 and 2). 
Braus was not able to say definitely whether or not in Bom- 
binator the suprascapula had a separate rudiment. He was 
able to recognize two thickenings in the dorsal zone (Braus, ’09, 
p. 175, fig. 5, scap., and fig. 7, Z) which, however, were not 
