2581. These are ascending rhythms (2528) in 3/8 time. The fundamental
foot is the Iambus (⏑ -́), for which its metrical equivalent the tribrach
⏑́ ⏑, the irrational spondee > -́, the irrational dactyl > ⏑́ ⏑, the cyclic
anapaest ⏑ -́, or the proceleusmatic ⏑ ⏑́ ⏑ is sometimes substituted.
2582. The Greek poets excluded all feet except the iambus and tribrach,
and in comedy the anapaest, from the even places in iambic verse. The
Latin poets were not so strict: but when one of the even feet was formed
by a word or a word-ending, they did not usually allow the foot to be a
spondee or an anapaest, but required it to be an iambus.