Degree of Injury and Rate of Regeneration 525 
TABLE 3 
Amblystoma opacum. Nos. 2000-2031. Individuals arranged in order of specific amounts of tail regen 
eration, twenty-four days after the operation 
TAIL ALONE! TAIL PLUS 
REMOVED | ALL LEGS 
| REMOVED 
0.22 
SEB) O35 
0.36 | 
0.37 
0.38 0.38 
0.40 
0.41 
Shorty 
ern 2e45 
0.48 
0.51 | 
| 9-57 
noticeable. The numbers of compared individuals in the three 
sets are eight, eight, and seven respectively beginning with the 
lowest injury. 
The following four experiments on Amblystoma (Nos. 6, 7, 
8 and g) were planned only partly with regard to the question of 
the effect of degree of injury on the rate of regeneration. ‘They 
give some data on the present problem, though in most cases the 
comparisons are merely between a very few individuals. 
6 Tail of the Larva of Amblystoma opacum. Nos. 967-990 
The rate of regeneration of the tail when it alone was removed 
was compared with the rate when one or both of the fore-legs 
were removed at the same time. 
From a mass of eggs belonging to a single salamander collected 
on October 1, 1905, the young were hatched on October 4. 
Twelve of the thirty larva are available for present purposes. 
Four groups of three individuals each were operated upon Novem- 
ber 8 and g and all the individuals were killed seventeen days 
