HYBRID DROSERA. 249 
in such epidermal cells. It will be more consonant with the principles of 
heredity if we suppose that at a certain cell centre in the epidermis a 
special growth-potentiality is inherited from one parent that stimulates 
to the formation of a hair characteristic of it, and that while the hereditary 
influence of the other parent, that is devoid of such hairs, is sufficient to 
reduce or check back growth of the hair to at least half the size of the 
parental one, it fails to prevent the development of a structure peculiar to 
one parent alone. Neither is there any need to suppose that there is a 
separation or sorting out of chromatic elements in the process. Side by 
side on the same spirem thread of the epidermal cell which produces 
such a hair elements of both parents may exist, and similiarly also in 
each cell that contributes to the hair formation. But the decidedly reduced 
size, in the hybrid, of the glandular hairs inherited from D. filiformis 
seems evidence that there is a marked prepotency of the chromatic 
substance of the other parent over the average. It is not too much to 
hope that some of these hypothetical problems my yet receive full veri- 
fication. 
