Degree of Injury and Rate of Regeneration 553 
TABLE ‘27 
Cambarus propinquus. Nos 2309-2378. Both chele removed. Regeneration for four molts after the 
operation 
Aen pars or | LENGTH OF | LENGTH OF | 
wumner | REGENERATION) REGENERATED | REGENERATED | 
| LEFT CHELA | RIGHT CHELA 
2317 28 3-92 4.00 Rate per day: 
2327 28 3.88 | 3 -88 | Rightchela =.140 mm. 
2343 28 3-92 | 3-85 Left chela =.140 mm. 
Average... 2... 28.0 | 3-91 3-91 
lute amount of regeneration of 3.07 mm. and a rate per day of 
0.110 mm. while the individuals with both chelea removed have 
an absolute amount of regeneration of 3.23 mm. and a rate per 
day of 0.114 mm. in each of the two chelea. For the four-molt 
cases the absolute amount for the single chela is 3.75 mm. against 
3-91 mm. for each of the chele in the double removal and the 
rates per day are respectively 0.135 mm. and 0.140 mm. 
18 Cambarus propinquus. Nos. 2391-2483 
Ninety-three young of the one hundred and four attached to 
a single female were used in the experiment which was concerned 
primarily with other factors than the one discussed in the present 
paper. These young had molted twice since hatching and were 
put into individual dishes on May 22, 1907. 
Those individuals which were operated upon one day after 
the third molt give data for the effect of the degree of injury 
Eight individuals with one chela removed and nine with both 
chelz removed survived until June 20, when all were killed. A 
comparison is thus obtained between the rate of regeneration 
of a chela when it alone is removed and its rate when the oppo- 
site chela is removed at the same time. 
The data are given in Tables 28 and 29. No measurements 
were made of cephalo-thoracic lengths or removed chela lengths 
and it is therefore not possible to make a comparison in terms 
of specific amounts and specific rates of regeneration. 
