Phystology of Regeneration 611 
the rate of regeneration was striking. This time only one-half 
the number of worms had regenerated at all, while the number 
of segments in the regenerated tails was only two. This will be 
seen from Table VI. 
TABLE VI 
AUGUST I0-16, 1908 | NUMBER OF SEGMENTS. AVERAGE 
Oldvsegntents i iocciece eons eixstse siete anstele ual TO. p20 TO) | TS Weta ers) tg. |) LOM ETA TO) et 7a8 
INewrSePMentssi..j100201sbs se '= staeetera re vere 7d We Seer Salle Pn Poel ee Ma AT eT CE PB 4-4 
Regenerated segment removed August 16 
bud| 0 
Ms 
PAU PR STO AUG Drresiotaieis siefoteteiol-teta:alvel ela/eis | bud 
AU Frey B= Se aby re ctaiecc'c) so eFm: ores) sists eyatoeeees 
° 2 2 2 2 2 3 2.1 
There was thus a most marked decrease in the rate of regenera- 
tion for the second period of 6 days as compared with that for 
the first 6 days. 
In the other set (see Table VII) the worms were allowed to 
regenerate for 12 days, at the end of which period they had regen- 
erated on the average a little more than five segments. The 
tails were cut off once more and the worms left to regenerate 
anew. ‘They were examined at the end of twelve days. Here 
again it was found that the rate of regeneration suffered a con- 
siderable reduction after the second operation, and though the 
length of time during which the worms were regenerating was 
the same in both cases, the number of regenerated segments was 
on the average greater by 1.5 segments after the first operation. 
TABLE VII 
AUG. IO-AUG. 22 NUMBER OF SEGMENTS AVERAGE 
1 | ia = 
Oldiseementssc re caeiclccetersiet 17 | 20 | 15 | 21 | 18 | 17 | 20 | 21 | 15 | 19 | 21 | 21 | 20 19 
New segments..........+.+. i Vek Baar 8 | Ble | 5 | (NF | aes | 8 Bee 
Regenerated segments removed August 22 
August 22 to September 3.. | Peles Zl tlh ay | 5 | dead pee 
August 22 to September g.. ; Beha Gee coil ae | dead | 5-2 
