Feather These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular "calamus" (or quill) which inserts into a follicle in the skin. The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus). Hatchling birds of some
Calamus (poems) Calamus (poems) The "Calamus" poems are a cluster of poems in "Leaves of Grass" by Walt Whitman. These poems celebrate and promote "the manly love of comrades". Most critics believe that these poems are Whitman's clearest expressions in print of his ideas about homosexual love. The first evidence of the poems that were to become the "Calamus" cluster is an unpublished manuscript sequence of twelve poems entitled "Live Oak With Moss," written in or before spring 1859. These poems were all incorporated in Whitman's 1860 edition of "Leaves of Grass", but out of their original sequence. These poems seem to