In, it was argued that Professor David Kaplan's model of S-explanation could be formulated so as to provide a unified framework for three types of explanation, viz., potential, rationally acceptable, and true. In this note I correct an error in the statement of the conditions for a potential direct S-explanans, show that the corrected version leads to a further simplification in the conditions of the model, and propose a fourth type of explanation which the framework of S-explanation can accommodate.