"Beta Life" was a term used in the influential Science of Life¹ encyclopedia by H. G. Wells, Julian Huxley, and G. P. Wells, to describe the kind of life that might exist on other worlds. The authors felt that if there were life on Mars, for example, it would be so different that it would have to be considered as something entirely new:

 

... an analogous thing and not the same thing. It may not be individualized; it may not consist of reproductive individuals. It may simply be mobile and metabolic. It is stretching a point to bring these two processes under one identical expression.

 

Reference

1. Wells, H. G., Huxley, Julian, and Wells, G. P. "Is There Extra-terrestrial Life?" In H. G. Wells, Julian Huxley, and G. P Wells, eds., The Science of Life, p. 11. New York: Doubleday (1931).