274 Evolution and Adaptation 
organized nature arranged in a discontinuous series of groups 
differing from each other by differences which are Specific; 
on the other hand, we see the diverse environments to which 
these forms are subject passing insensibly into each other. 
We must admit, then, that if the steps by which the diverse 
forms of life have varied from each other have been insensi- 
ble, — if, in fact, the forms ever made up a continuous series, 
—these forms cannot have been broken into a discontinuous 
series of groups by a continuous environment, whether acting 
directly as Lamarck would have, or as selective agent as Dar- 
win would have. This supposition has been generally made 
and admitted, but in the absence of evidence as to Variation 
it is nevertheless a gratuitous assumption, and, as a matter of 
fact, when the evidence as to Variation is studied, it will be 
found to be in a great measure unfounded.” 
There is a fair number of cases on record in which discon- 
tinuous variations have been seen to take place. Darwin him- 
self has given a number of excellent examples, and Bateson, 
in the volume referred to above, has brought together a large 
and valuable collection of facts of this kind. 
Some of the most remarkable of these instances have been 
already referred to and need only be mentioned here. The 
black-shouldered peacock, the ancon ram, the turnspit dog, 
the merino sheep, tailless and hornless animals, are all cases 
in point. In several of these it has been discovered that the 
young inherit the peculiarities of their parents if the new 
variations are bred together; and what is more striking, if 
the new variation is crossed with the parent form, the young 
are like one or the other parent, and not intermediate in 
character. This latter point raises a question of fundamental 
importance in connection with the origin of species. 
Darwin states that he knows of xo cases in which, when 
different species or cven strongly markcd varieties are crossed, 
the hybrids are like one form or the other. They show, he be- 
lieves, always a blending of the peculiarities of the two parents. 
