132 Francs B. Sumner 
Until further data are available, however, it seems worth while 
to offer them for what they are worth. 
Fig. 9 shows the distribution of hair weight for the entire lot, 
both the hot room and the cold room individuals. No fair com- 
parison can be drawn from these polygons, as has already 
been stated, since mice of very different sizes are represented. In 
Fig. 1o I have substituted in each case for the absolute weight 
the ratio of the hair weight to the square of the body length. While 
the modes lie at the same point, the centers of gravity are con- 
siderably separated. 
In view of statements cited by Lydekker® regarding certain 
modifications which are alleged to have been produced in cats by 
Fig. 10 Series of 1907-1908: weight of hair (relative) of “‘unmated males” at 24 months (= ratio 
of hair-weight to square of body length). 3 ake 
life in a cold-storage warehouse, I endeavored to determine for 
the present group of mice whether there was any appreciable dif- 
ference in the length of the vibrissae between cold room and warm 
room individuals. The measurements have necessarily been 
rough in the extreme. The longest hair among the “whiskers” 
of one side was measured by calipers, without straightening or 
removing it. The mean figures obtained were 26.8 mm. for the 
warm room lot; 25.4 for the cold room lot. Considering the crud- 
ity of the method, the individual measurements vary compara- 
- ® A Handbook to the Carnivora. Part I: Cats, etc.; pp. 158-163. 
