§1. The purpose of this treatise is to discuss the use in Plautus and Terence of the endings of the third person plural perfect indicative active: -ēre,-ērunt, and -ěrunt. The relation of these three endings in Latin has remained doubtful, chiefly because it has been impossible to determine their relation in the comedies of Plautus and Terence, the earliest Latin literary works that have survived in fairly complete form. No complete and thoroughgoing presentation of the material available for a study of the endings in these authors has appeared. It was therefore the hope of the present writer that a careful examination of all the verses in which the forms occur, might yield new results, or at least more precise information on the occurrences of each ending. My conclusions regarding the number of times each ending occurs in Plautus and Terence do not differ essentially from conclusions previously reached, but the material seems to be definite and extensive enough to justify an attempt to account for the use of the endings. The evidence found to explain this has determined the present form of my treatise. In view of the complicated nature of the problems concerned, I have preferred to present the facts first, then to deduce probable explanations for the usages in Plautus and in Terence. Finally, some suggestions are added as to the possibility of applying the explanations derived from these authors to established facts concerning the later history of the endings.