No. 399.] NOTES ON PLANARIANS. 175 
Days. I. | 2. 3. 4. 5. 
I 235. EE IO X I 6 x .5 9 X 75 
5 y. 5.5 X <5 2X1 Ox 4 8x 3$ 
12 6.5 6 4 Xx 533 6 x .66 Dead. yx: 
17 6X .5 4 X .33 $ X4 4X.3 
i35 us 
23 4X-.5 25x55 43 X -5 esi E 
E ID. **]-Cut in two. edad s aene 
1.25 X .3 (tail) 
L26 x 3 1.75 X .3 (head) 
(head) 1.25 X .3 (tail 
2 
f 37.4 Partial regen- T5 Partial regenera- 
eration. Died. tion. 
I.4 X .3 (head) 
.9 X .3 (tail) 
Complete  re- 
two days later. 
40 2:3 X..4 2.7 X4 Bik ad 
2.28 X «4 6 x .25 
Cut in two. Lost by accident. 
Tail end, 1.1 : 
1.9 X .4 X .45 ge 
43 Cut in two. erated in four 
Parts died in days (partly). 
two days. Head end, .9| 
little new tis- 
sue. 
Table giving history of five planarians in distilled water. The vertical columns 
should be read separately. There is a slight discrepancy in the measurements of 
? and 3 for 17 and 23 days, no doubt due to an error in observation. The 
column to the left gives the number of days from the beginning of the experiment. 
The measurements, made after 17 days with the ocular micrometer, have all been 
reduced to millimeters. 
