Verses Trivocular

Of one scrap of science I've evidence ocular.
A heart of one chamber they call unilocular,
And in a sharp frost, or when snow-flakes fall floccular,
Your wise man of old wrapp'd himself in a Roquelaure,
Which was called a Wrap-rascal when folks would be jocular.
And shell-fish, the small, Periwinkle and Cockle are,
So with them will I finish these verses trivocular.