Effect of Age upon Regeneration 581 
TABLE 9 
Amblystoma jeffersonianum. Nos. 2032-2076. First regeneration. Older individuals. Regenera- 
tion period = 14 days (Fune 6 to Fune 20, 1907). Age at time of operation = 131 days 
PART OF | SPECIFIC | SPECIFIC 
TOTAL LENGTH OF | LENGTH OF | 
CATALOGUE| TAIL RE- TAIL AMOUNT OF| RATE OF 
LENGTH OF REMOVED REGENER- | 
NUMBER MOVED LENGTH REGENERA- | REGENERA- 
ANIMALS TAIL ATED TAIL | 
(APPROX.) | TED TAIL | TION 
| | 
2032 whole 51.5 24.5 18.5 4.2 0.23 | 0.016 
2042 whole 52.0 A) 20.2 5.0 0.25 0.018 
2055 whole 48.5 24.4 20.2 3-6 0.18 0.013 
2056 whole 52.1 26.0 20.4 3-2 0.16 0.011 
2074 whole 54.0 Phi 23-1 Gea 0.22 0.016 
PAVETASEN eels| pean ae 51.62 25.54 20.48 4.22 0.208 0.0148 
2048 half 48.3 22s Lhe 5 2.8 0.24 0.017 
2057 half Si) PEs sel 13.8 Bol 0.25 0.018 
2064 half 47-5 2365 10.4 3.0 0.29 0.021 
2062 third 49.0 24.9 8.1 2.7 0.33 0.024 
Average ...|.0...--.+-- 49.12 24.05 10.95 gid) 0.277 0.020 
