(syn. Horizocerus Ϯ Eastern Long-tailed Hornbill H. cassini) Gr. τροπις tropis ship’s keel; κρανος kranos helmet; "Genus ORTHOLOPHUS. It has been pointed out to me by Mr. Tom Iredale that this genus, introduced by Mr. Ogilvie-Grant (Cat. Birds Brit. Mus. xvii. p. 424, 1892) for two West African Hornbills, is preoccupied by Ortholophus Bigot, Bull. Soc. Ent. Fr. (6) ii. p. 129 (1882), for a genus of Diptera. I propose to substitute Tropicranus, gen. nov., for Mr Ogilvie-Grant's Ortholophus with type Ortholophus cassini Finsch ... The name derives from τροπις, a keel, and κρανος, a helmet." (W. Sclater 1922).