In Greek, past tenses are formed with "augmentation," e.g. present -> imperfect:

* λῡ́ω > ἔλῡον
* εὑρῐ́σκω > ηὕρῐσκον

Since we know that certain Latin verbs [preserve perfect reduplication](http://latin.stackexchange.com/questions/606/which-verbs-have-reduplicated-perfect-stems), I wonder: **do any Latin verbs also preserve a temporal augment**? One potential example immediately comes to mind: *ago > egi*.

If so, **is there any rule we can point to by which some Latin perfect stems are reduplicated, others are augmented, and the rest are formed according to the normal rules?**