The Roundabout is advertising its latest Stage One production as D.H. Lawrence's ''The Fox.'' The designation is not altogether accurate. Except for his melodramatic climax, adapter Allan Miller has remained generally faithful to the outlines of the original situation. But there have been some serious losses in the transfer from page to stage.
''The Fox'' relates how mannish Nellie March (Jenny O'Hara) and impulsively feminine Jill Banford (Mary Layne) give shelter to Henry Grenfel (Anthony Heald) , a World War I soldier who turns up at the isolated farmstead where the two women are living. Grenfel becomes a kind of temporary handyman. Before long, he shoots the fox that has been killing their chickens. With a cunning that masquerades as innocence, the soldier ingratiates himself. He woos and wins the at-first-resistant Nellie and literally destroys Jill in the process.
As developed by Lawrence, ''The Fox,'' with its subjective underlayers and symbolic elements, created a conflict in which realism was heightened by an accompanying extra dimension of undefined fear and apprehension. (Near the end of the tale, he refers to ''the awful mistake of happiness.'')
Although the Roundabout cast achieves a reasonable degree of tension and emotional substance, the performance staged by Mr. Miller seems to reflect artifice rather than deep conviction. As a result, the brooding drama in the dimly lighted farmhouse kitchen designed by Roger Mooney scarcely serves to rivet the attention. It's a dreary November on the old Bailey Farm.