550 Charles Zeleny 
TABLE 23 
Cambarus bartoni. Third regeneration. Both chele removed. Two molts 
a | = z | SPECIFIC | SPECIFIC 
S time | CEPHALO-THORACIC | a a | LENGTH OF |.ounr Gr| RATE OF 
z INTER- LENGIM a 3 | REGENERATED | 2 GENERA-| REGENERA- 
Seen el evAL IN e Paceccce TION | ‘TION 
3S BAte enn kl 5 mises | : oe | toe 
a8 Molt | Molt | Molt (4, 4. | nes" | eal 
Seal 8 9 10 8-9 Left | Right | Lett oe Left |Right 
2245 | 8-9-10| 47 10.5 | 11.8 WIA)! Guleily || ate) 6.4 | 0.63] 0.57) 0.013/0.012 
2253 | 8-g-10] 52 FO.4 | TTS | Ta.4 tl resg5) 16270 | (Osseat 0.61 0.62) 0.012\0.012 
ar ad Re | 
PA VGA CC eetetteesetats 49-5 | 10.45 | 11.65 | 12.6 11.05 | 6.85 | 6.6 | 0.62/0.505/0.0125\0.012 
and 0.62 and 0.595 for the left and right chele respectively in 
double removals. Likewise, the specific rate 1s 0.0119 for the 
single chela and 0.0125 and 0.0120 for the left and right chela 
respectively in double removals. 
For the third regenerations again the advantage is in favor of 
the crayfish with the greater injury. 
Fourth Regeneration 
Only four crayfish had a fourth regeneration. The regenera- 
tion in all extended through a single molt only. In three cases 
with a single chela removed the average absolute amount was 
6.5 mm., the specific amount 0.52 and the specific rate 0.019. 
In the one case with both chele removed the average of the two 
chela gave an absolute amount of 5.5 mm., a specific amount 
of 0.46 and a specific rate of 0.021. The first two values are 
greater in the crayfish with the lesser injury, the last one is greater 
in the animal with the greater injury. “The number of individuals 
is too small to make the result of much value. 
Taking the present experiment as a whole it is very evident 
that in young crayfish the advantage is distinctly in favor of 
the chela with a regenerating mate, as opposed to a chela 
removed and regenerating alone. 
