Certainly, if you count the syllables on your fingers, there are ten syllables in each line: of that I am perfectly aware; but the lines are none the less belonging to the species of versification called octosyllabic.
"The Letters of Elizabeth Barrett Browning (1 of 2)"
Frederic G. Kenyon
This paper has exceeded the length we designed to give it; but, nevertheless, we beg the reader's indulgence for a few moments longer, while we conclude with an octosyllabic version of the last thirty lines of the celebrated Ugolino story.
"Essays Æsthetical"
George Calvert
Dyer's Grongar Hill, which mingles reflection with natural description in the manner of Gray's Elegy written in a Country Churchyard, was composed in the octosyllabic verse of Milton's L'Allegro and Il Penseroso.
"Brief History of English and American Literature"
Henry A. Beers