iambus

He was considered the inventor of parody and of a peculiar metre, the scazon or choliambus, which substitutes a spondee for the final iambus of an iambic senarius, and is an appropriate form for the burlesque character of his poems.

Iambus, ī-am′bus, n. a metrical foot of two syllables, the first short and the second long, as in L. fĭdēs; or the first unaccented and the second accented, as in deduce—also Iamb′.—adj.

Antispast, an′ti-spast, n. in metre, a foot composed of an iambus and a trochee.—adj.

Choliamb, kō′li-amb, n. a variety of iambic trimeter, having a trochee for an iambus as the sixth foot.—adj.

Here's another criticism: The "Without" and "Within," beginning the first and third lines, respectively, seem to be antithetic, when they are not, the latter having the sense of "into," which I think might, for clearness, be substituted for it without a displeasing break of the metre—a trochee for an iambus.