[961.] (d.) With the present stem in -io|e- ([836]).

quatiō, shakequatere-cussīquassus

Compounds drop the a ([111, a]): as, in-cutiō, in-cutere, in-cussī, in-cussus.

PERFECT STEM IN -v-.

[962.] (2 a.) The following verbs in -ere have the perfect stem in -v-, preceded by a long vowel of the root ([869]), and the perfect participle, when used, in -tus:

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

terō, rubtereretrīvītrītus

Perfect infinitive once in pentameter verse ([823]) at-teruisse (Tib.).

[964.] (b.) With the present stem in -no|e- ([833]).

cernō, sift, separate, seecernerecrēvī, decidedcertus, -crētus
linō, besmearlinerelēvī, rarely līvīlitus