I n t r o d u c t i o n. The main object of this paper is to simplify the usual framework for predicate logic (with identity). The motivation is analogous to that of the preceding papers of Tarski [14] and of Kalish and Montague [11]. In those papers, working with the ordinary rules of formula formation, the authors give very simple axiom systems for the universally valid formulas and sentences of predicate logic. Thus in describing the axioms of system ~ of [14] only two notions of any degree of complexity at all appear: the notion of the set of variables occurring in a formula, and the notion of substituting one variable for another in an atomic formula. By modifying the formation rules of predicate logic we will be able to eliminate this last notion.The modification consists in having after each non-logical predicate a fixed string of variables depending upon the particular predicate but not changing for different occurrences of the same predicate. Identity is considered as a logical notion, and so full substitution is allowed in atomic identity formulas. The possibility of still obtaining an adequate system of predicate logic using this formation rule may be illustrated by the following example. In ordinary logic, let ~ be a binary predicate. Then the formula