238 
The two columns show that there is a striking deviation from the 
calculated results, the result of a marked correlation in the variation or 
tendency to or toward bilateral symmetry. As calculated, the chance 
association of the same number of scales on the two sides would occur 115 
times for all combinations, it actually occurs 187 times. The specimens 
fall into several definite groups in which the same number of scales on 
each side forms the center of a group. This is not quite true at the ex- 
tremes, but is especially marked in the central groups into which the 
large majority of the specimens fall. There are three specimens in the 
first group, each of which has 40 scales on the right side. One has 40 
scales on the left side, one 42, and one 43. The greatest difference in 
the number on the two sides is three. There are three specimens in the 
first group of the calculated column. Each has 40 scales on the right side, 
one has 43 on the left, one 44 and one 45. ‘he greatest difference in this 
case is five, and none have the same number on both sides. In the second 
group of the actual column there are seyen specimens, two with 41 scales 
on each side, two with 41 on the right side and 42 on the left, two with 
41 on the right and 48 on the left, and one with 41 on the right and 44 on 
the left. The greatest difference in the number of scales on the two sides 
is three. There are seven specimens in the second group of the calculated 
column. Each has 41 scales on the right side and on the left side one has 
42, two have 43, two 44, one 45, and one 46. As in the first group of this 
column, none have the same number on both sides, and the greatest differ- 
ence is five. The number of specimens in the fourth group of the actual 
column is 126. Each has 43 scales on the right side, and on the left three 
have 41, fifteen 42, fifty-six 43, thirty-seven 44, thirteen 45 and two 46. 
The largest number of individuals in this group which have the same 
combination, have the same number of scales on both sides, and the 
greatest difference in the number on the two sides as in the other cases 
is three. The calculated column of the same group contains 125 speci- 
mens, each of which has 43 scales on the right side. On the left side, two 
have 41, eleven have 42, thirty-four 43, forty-two 44, twenty-three 45, ten 
46, two 47 and one 48. The largest number in this case with the same 
combination has 43 scales on the right side and 44 on the left, and the 
greatest difference, as before, is five. 
The number of specimens in the same groups of the two columns is 
the same in most cases, and in no case is there a difference of more than 
one. This difference is perhaps due to the dropping and adding of frac- 
