Compounds have i for a: as, re-sipiō, &c.

[970.] (d.) With the present stem in -sso|e- ([375]).

ar-cēssō, send forar-cēsserear-cēssīvīar-cēssītus

Sometimes ac-cersō, &c.; infinitive rarely ar-cēssīrī or ac-cersīrī.

capēssō, undertakecapēsserecapēssīvī——
facēssō, do, make offfacēsserefacēssīvīfacēssītus

Perfect system rare: facēssierīs or facēsserīs (Cic.), facēssīsset (Tac.).

in-cēssō, attackin-cēsserein-cēssīvī——
lacēssō, provokelacēsserelacēssīvīlacēssītus

PERFECT STEM IN -u-.

[971.] (3.) The following verbs in -ere have the perfect stem in -u- ([873]), and the perfect participle, when used, in -tus; in some participles -tus is preceded by a short i, thus, -itus ([910]):

[972.] (a.) With the present stem in -o|e- ([829]).