BIOMETRY 375 
more or less of the blue color and markings of the wild rock pigeon 
from which domestic pigeons are presumably descended. He described 
many cases of dogs, cattle and swine, as well as many cultivated 
plants, in which offspring resembled distant ancestors and differed 
from nearer ones; such cases had long been known and were spoken 
of as “‘reversion.”” He observed many cases in which certain charac- 
ters of one parent prevailed over corresponding characters of the 
other parent in the offspring, this being known as “‘prepotency”’; 
but there was no satisfactory explanation of these curious phenomena. 
They did not come under either of Galton’s laws, and their occur- 
rence was apparently so irregular that every such case seemed to be 
a law unto itself. 
