656 TELEOSTEI CHAP. 
the seas nearly all over the world. But one freshwater form is 
known, Aphredoderus sayanus, the little Pirate Perch of North 
America, growing to 5 inches in length. The largest marine 
forms (Beryx and Gephyroberyx) measure from 1 to 2 feet. 
Recent genera: Leryx, Polymixia, Aphredoderus, Melamphaes, 
Plectromus, Scopelogadus, Anoplogaster, Caulolepis, Trachichthys, 
Paratrachichthys, Gephyroberyx, Myripristis, Holocentrum. 
Fic. 401.—Hoplopteryx lewesiensis. (Restored by A. S. Woodward.) 
Fossil genera: Sphenocephalus, Acrogaster, Pycnosterinz, 
Hoplopteryz, trom the Upper Cretaceous. <Asineops, from the 
Eocene of North America, is supposed to be allied to Aphredo- 
derus. Beryxz is represented by several species in the Upper 
Cretaceous, and Holocentrum occurs in the Eocene and Miocene. 
Fam. 2. Monocentridae.—The single genus J/onocentris, 
with two species, one from the seas of Japan, China, and India, 
and one from the South Pacific, is very nearly related to the 
Berycidae, but differs in the absence of ribs on the anterior six 
vertebrae, in the very large bony scales, forming together a coat 
of mail, and in the structure of the ventral fin, which is reduced 
to a strong spine and two or three very short soft rays. The 
spines of the dorsal fin are very strong and isolated. 
Fam. 3. Pempheridae.—The resemblance which the fishes 
united under this family bear to Beryx is very striking, and 
applies to the skeleton as well as to the external characters. But 
the ventral fins are formed of one spine and five soft rays, as 
in most Acanthopterygians. Dathyclupea agrees with Beryx in 
