680 TELEOSTEI CHAP. 
seas. our or five species are distinguishable, and are referable 
to two genera: Histiophorus, with a single dorsal fin and 2 or 3 
ventral rays, and 7etrapturus, with the dorsal divided into. two 
parts and a single ventral ray.’ 
Fossil Histiophoridae are known from the Eocene and later 
beds in Europe and America. Dr. A. 8. Woodward observes that 
the known fossils are too imperfect to be referred with certainty 
to their respective genera. Most of them probably belong to 
Histiophorus, but at least one genus from the Eocene (Aiphio- 
rhynchus) appears to be well distinguished. 
=o oeEeS ona — 
Meare BETO S= 
; Pole a TNSS = 
Ae IEG S 
\ SS 
Fic. 416.—Tetrapturus belone, from the Mediterranean. (After Cuvier and 
Valenciennes.) x 5. 
The imperfectly known extinct family Palaeorhynchidae, from 
the seas of the Eocene, Oligocene, and Miocene periods, with the 
genera Palaeorhynchus and Hemirhynchus, is probably closely 
related to the Histiophoridae. The vertebrae number 50 to 60, 
and the ribs completely encircle the body. In Palaeorhynchus 
both jaws are equally produced into an ensiform weapon. 
Llochius, from the Eocene, with diamond-shaped, slightly over- 
lapping bony seutes on the body, is perhaps also to be placed 
near this family. 
' For a detailed account of these fishes and of Xiphias, ef. Brown Goode, Proc. 
U.S, Mus. iv. 1881, p. 415, and Rep. U.S. Fish Comm. f. 1880, 1883, p. 289. 
