In languages like English, reflexivity and reciprocity are expressed by distinct proforms. However, many languages, such as Cheyenne, express reflexivity and reciprocity with a single proform. In this paper I utilize Dynamic Plural Logic (van den Berg, 1996) to a draw a semantic parallel between reflexive and reciprocal anaphors in English. I propose that they contribute overlapping but distinct requirements on the relations introduced by transitive verbs, requirements which fully specify reflexivity and reciprocity. This parallel is then extended to Cheyenne (...) by appealing to underspecification. I propose the Cheyenne affix which expresses both reflexivity and reciprocity contributes only the shared requirement of the English anaphors. It is thus underspecified, not ambiguous. This accounts for its compatibility with both singular and plural antecedents as well as its variety of construals. (shrink)