SHOULDER GIRDLE AND ANTERIOR LIMB 5 yA | 
Since the region of mesoderm shown in text figure 2, when ex- 
tirpated, frequently includes the entire girdle rudiment, it is 
obvious that when transplanted all or nearly all of the rudiment 
is included in the transplant. 
When such transplantations were made it was found that the 
girdles which had developed at the place of implantation were 
almost as large as the normal girdles (fig. 20). Figure 19 repre- 
sents a section through the normal girdle of individual D 29 
preserved twenty-four days after the operation. Figure 20 shows 
a section through the implanted girdle. When these two girdles 
are compared and measured it is found that the implanted girdle 
is about three-fourths as large as the normal one. In individual 
D 41 preserved twenty-seven days after the operation the im- 
planted girdle was also found to be three-fourths:as large as the 
normal. In this case, as well as others, the implanted mesoderm 
was placed so near to the normal limb region that there was 
partial fusion of the two girdles. In individual D 23 preserved 
twenty-four days after the operation, the implanted girdle was 
larger than in all other operated cases studied, ‘it being four- 
fifths the size of the normal. The dorsal zone was typical in 
shape, although the ventral zone was broader and not quite as 
long as that of the normal. There was also partial fusion of the 
two girdles. 
The fact that double limbs frequently arise from a single trans- 
planted rudiment has already been shown (Braus, ’04 b, and 
Harrison, ’07). When double limbs develop from transplants 
which are placed near the normal limb rudiment, the anterior 
of the two frequently unites with the normal limb to form a 
fused double limb, while the posterior member of the reduplica- 
tion remains single. This condition was met with in individual 
D 23. Although the anterior member had fused with the nor- 
mal limb, its shoulder joint was formed on the implanted girdle. 
A separate shoulder joint was formed some distance posterior 
and ventral to this for the reception of the posterior member of 
the reduplication. Other cases have shown that there may be 
only one shoulder joint for both members of a double limb. The 
formation of double limbs therefore does not mean the formation 
