The malleus bone bridges the gap between the eardrum and the other ossicles. The stapes is the third bone of the three ossicles in the middle ear. The ossicles (malleus, incus and stapes) normally appear during the first half of fetal development. The middle ear includes the tympanic cavity and the three ossicles. The stapes is one of three ossicles in mammals. It is the first of the three ossicles, and attached to the tympanic membrane. His phonautograph was constructed as an analog of the ear canal, eardrum and ossicles. The walls of this have chitinous ridges, teeth and calcareous ossicles. The dermis contains an endoskeleton of calcium carbonate components known as ossicles. Echinoderms have a mesodermal skeleton composed of calcareous plates or ossicles. This endoskeleton is composed of plates called ossicles. Just below their skin is an endoskeleton composed of calcareous plates or ossicles. The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The middle ear consists of a space spanned by three small bones called the ossicles. The anvil-shaped small bone is one of three ossicles in the middle ear.