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, Iowa located in Wheatland, Iowa. The school is part of the Calamus-Wheatland Community School District, and has an enrollment of approximately 120 students in grades nine through 12. http://www.cal-wheat.k12.ia.us/ Calamus has 4 county parks: Calamus, Iowa Calamus is a small town in Clinton County, Iowa, United States located on the historical Lincoln Highway, which was the first transcontinental highway for automobiles across the U.S.. Calamus is the only town in Olive Township and had a population of 439 at the 2010 census, which was an 11.4% increase from the 2000 census. Calamus was named after Calamus creek, which received its name