Ostracion cubicus is a four-angled species, and when the trunkfishes were regarded as a family (Ostraciidæ), the three-angled ones were set off as a separate genus. For this two names were offered, both by Swainson in 1839. For trigonus, a species without horns before the eyes, he gave the name Lactophrys, and for triqueter, a species without spines anywhere, the name of Rhinesomus. Most recent American authors have placed the three-cornered species which are mostly American in one genus, which must therefore be called Lactophrys. Of this name Rhinesomus is a synonym, and our species should stand as Lactophrys tricornis. The fact that Lactophrys as a word (from Latin lætus, smooth; Greek ὀφρύς, eyebrow; or else from lactoria, a milk cow, and ὀφρύς) is either meaningless or incorrectly written makes no difference with the necessity for its use.
Fig. 241.—Spotted Trunkfish, Lactophrys bicaudalis (Linnæus). Cozumel Island, Yucatan.
Fig. 242.—Spotted Trunkfish (face view), Lactophrys bicaudalis (Linnæus).
In 1862, Bleeker undertook to divide these fishes differently. Placing all the hornless species, whether three-angled or four-angled, in Ostracion, he proposed the name Acanthostracion for the species with horns, tricornis being the type. But Acanthostracion has not been usually adopted except as the name of a section under Lactophrys. The three-angled American species are usually set apart from the four-angled species of Asia, and our cuckold is called Lactophrys tricornis. But it may be with perfect correctness called Ostracion tricorne, in the spirit called conservative. Or with the "radical" systematists we may accept the finer definition and again correctly call it Acanthostracion tricorne. But to call it quadricornis or listeri or maculatus with any generic name whatever would be to violate the law of priority.
Fig. 243.—Spineless Trunkfish, Lactophrys triqueter (Linnæus). Tortugas.
Trinomial Nomenclature.—By trinomial nomenclature we mean the use of a second subordinate specific name to designate a geographic subspecies, variety, or other intergrading race. Thus Salmo clarki virginalis indicates the variety of Clark's trout, or the cut-throat trout, found in the lakes and streams of the Great Basin of Utah, as distinguished from the genuine Salmo clarkii of the Columbia. Trinomials are not much used among fishes, as we are not yet able to give many of the local forms correct and adequate definition such as is awarded to similar variations among birds and mammals. Usually varieties in ichthyology count as species or as nothing.
