INEQUALITIES IN HOMOLOGOUS CHROMOSOMES eal 
see many reasons to suppose that De Vries was dealing, in part 
of his mutants at least, with something similar to what I have 
described in this paper as deficient homologous chromosomes. 
Deficient chromosomes, such as I have found paired with 
their normal sized mates in Tettigidea parvipennis, it seems 
to me, furnish a sufficient explanation for the loss of unit factors 
from the germ plasm. Looked at in the light we now have of 
the behavior of unit characters which belong to this ‘loss’ group, 
the hypothesis appears very probable. It seems to me that 
Professor Morgan and his students, who are working upon 
Drosophila, should also take into consideration the possibility 
of such deficient chromosomes. [It is a good working hypothe- 
sis, and I am going ahead with breeding experiments upon this 
species, Tettigidea parvipennis, in the hope of getting some results. 
As to what connections there may be between these deficient 
chromosomes and the greater problem—the origin of new char- 
acters—it is difficult to imagine. This matter had better be 
left until we have more knowledge of the behavior of these 
chromosomes. 
The observational work upon which this paper is based was 
done at Harvard University under the direction of Prof. EK. L. 
Mark. The writing was completed at Kansas University. I 
wish to express here my gratitude to Dr. Mark for the help and 
criticism he bas so kindly given to me from time to time. 
