a kind of oven, or reverberatory furnace, used for the calcination of sand and potash, and converting them into frit.-a hollow tube or spur at the base of a petal or corolla.-a slender bony process from the ankle joint of bats, which helps to support the posterior part of the web, in flight.-a spur, or spurlike prominence.-a curved ridge in the floor of the leteral ventricle of the brain; the calcar avis, hippocampus minor, or ergot.