14 PROF. JULIUS MACLEOD ON TEN 
$ 10. PERCENTAGE CURVES (continued).— Comparison between several cha- 
racters of the same species. Table VIII. enables us to compare the gradation 
of four characters of the leaves of M. hornum by means of their mean 
percentage curves (eight specimens belonging to the same patch). The 
absolute values are given in the descriptive table of M. hornum. 
TABLE VIII. 
Mnium hornum, Linn.—Mean percentage curves of the gradation of four 
characters. Hight stems (340 leaves). See fig. 3. 
Intervals: 1. 2. 8. 4. 5. 6. T. 8. 9. 10. 
IDSIOUR d uus B BER AB dB. DD 09 00. 7/7 89 100 
Toys vcl c DD MEM H0 2584 09. 4^ — 94. 107. 111^:120^ 191 —TO0 
Number of cells at the 
place of the greatest | 80 5:05... 70 00- 108 114. 1190- 194 :194 . 100 
DISSE S ose ck. ] 
Breadth of those cells...... 67 73 78; 385 ..-80 94 94 94 100 100 
ie 
E 
VA 
N/K 
Ty 
f D 
0 A 
E 
L 
22 X wae 8 7.93 35 19 
Fro, 9.— The curves represent the figures in Table VIII. Z, length of the leaves; 
Bi, breadth of the leaves; Ne, number of cells; Be, breadth of the cells. 
We see here (fig. 3) more examples of the independence of the gradation 
curves; the curves L, Bc, and Ne are, indeed, quite different. 
The curve B? is interesting. The character Bl (breadth of the leaves) depends 
on the whole on two factors: the number of cells (in the transverse direction) and 
