140 Experimental Zoology 
viduals may be designated by 12345 and the bandless by 220°, 
12345 ©0000 
The young of the first generation are all without bands. In other 
words, the banded condition is the recessive. The formula used 
00000 d 
123457 
When the individuals of the first generation (F) are paired, the 
offspring of the second generation are of two sorts (like the grand- 
parents). Those having the dominating character (bandless) 
are to those with bands as 3 to1. In other words, the Mendelian 
ratio appears. That this is really the case is shown by further 
12345 
12345" 
and produce only banded offspring. The bandless are of two 
C0000 
by Lang for these individuals is 
experiments. The banded individuals are the recessives, 
kinds, one third true or “pure” dominants, » and two 
thirds dominant recessives, ie There are no external char- 
acters that distinguish the pure dominants from the dominant 
recessives, since both are bandless; but if they are separated in 
pairs and their offspring obtained, it will be found that in some 
cases all of the offspring will be bandless. They have arisen 
©0000 | 00000 
, or by 
©0000 00000 
the union of one extracted dominant and of one dominant reces- 
OQ0000 x 00000 
©0009 12345" 
are bandless and one third banded, showing that two dominant 
00000 00000 
12345 12345 
Lang has also carried out some experiments with snails in’ 
which two characters are involved. The individuals of Helix 
nemoralis or of H. hortensis differ not only in their banding but 
also in the color of the shell, which may be yellow or red. These 
colors also form a pair of antagonists that follow the Mendelian 
law. The double combination of banded and bandless, yellow 
and red, gives the Mendelian expectation for two contrasted 
characters. 
by the union of two extracted dominants, 
sive, In other cases two thirds of the offspring 
recessives have paired, 
