The mouth of the pitcher has a corrugated rim (peristome) formed by incurving of the margin, the convex surface of which is firm and shining.
The head is long, heavy and ugly, the nose coarse and prominent, with the horns situated close together, often continuing parallel almost to the extremities, being also large, corrugated and pointed.
Yarnold's process, using corrugated glass plates coated on one side with gold or other metal leaf, is stated to have yielded as much as 2700 grains per e.h.p. hour.
Calyx of some species of clematis and of some herbaceous plants, or rolled up at the edges (involute or revolute), or folded transversely, becoming crumpled or corrugated, as in the poppy.
" Lean-to," " shed," or " pent " roofs are practically developments of the flat roof, one end of the joists (which are now called " rafters ") being tipped up to form a decided slope, which enables slates, tiles, corrugated iron and other materials to be employed which cannot be used upon a " flat " roof.