Shell: The shell, when young, is spiral and, thin. When adult,it is white, solid, tubular and spiral for three or four
whorls. The
body whorl is prolonged into an irregular, straight or flexuous tube, solid posteriorly, and with a siphonal keel on the left side.
This curious genus lives in coral, and the inordinate extension of the lips of the shell is to enable the animal
to keep on a level with the surface of the coral as it continues to increase in size. As the shell grows, the tube
behind is filled up with solid calcareous matter.[2]
Magilus costatus G. B. Sowerby II, 1872: synonym of Magilus sowerbyi Massin, 1982 (invalid: junior homonym of Magilus costatus Chenu, 1843; M. sowerbyi is a replacement name)
Magilus cumingii (H. Adams & A. Adams, 1864): synonym of Coralliophila cumingii (H. Adams & A. Adams, 1864)
Magilus macrocephalus G. B. Sowerby III, 1919: synonym of Magilus microcephalus G. B. Sowerby II, 1872: synonym of Magilus antiquus Montfort, 1810 (described in synonymy)
Magilus microcephalus Sowerby, G.B. III, 1872: synonym of Magilus antiquus
Magilus peronii Lamarck, J.B.P.A. de, 1818: synonym of Magilus antiquus
Magilus serratus Sowerby, G.B. III, 1872: synonym of Magilus antiquus
Magilus solidiusculus G. B. Sowerby II, 1872: synonym of Leptoconchus solidiusculus (G. B. Sowerby II, 1872) (original combination)