HN 
Mn 
| 
7\ 
tail length at six weeks of age (sexes combined). Abscissas denote tail length in millimeters; ordinates denote number of individuals. 
ul 
ul 
— 
| 
——— 
-— 
-————} 
_——| 
— 
—— 
_—— 
-— 
60 6l 
52) Sd C4 Oo OG morn oo) cso 
LA 
Mn 
MN 
I 
pitt 
went 
ul 
nm 
“ 
INI 
45 46 47 48 49 50 SI 
ils 
Mi 
Hi 
39 40 4) 
Shading as before. 
. 
Fig. 3 Series of 1907-1908 
