COCCYGEAL BODY This is a median body, the size of a pea, situated in front of the apex of the coccyx and between the insertions of the levatores ani muscles. It resembles the carotid body in its microscopical struc ture, but is not so vascular. Concentric corpuscles, like those of the thymus, have been recorded in it. Of its embryology and com parative anatomy little is known. Probably it is sympathetic in origin. (For further information see ENDOCRINOLOGY.) BIBLIOGRAPHY.-Quain's Anatomy, vol. i (1908) ; McMurrich's Bibliography.-Quain's Anatomy, vol. i (1908) ; McMurrich's Development of the Human Body (1906) ; Wiedersheim's Vergleich. Anat. der Wirbeltiere (Jena, 1898) .