268 



Percomorphi 



Trichiurus lepturus is rather common on our Atlantic coast. 

 The names hairfish and silver-eel, among others, are often given 

 to it. Trichiurus japonicus, a very similar species, is common 



FIG. 209. Cutlass-fish, Trichiurus lepturus Linnaeus. 



Fla. 



in Japan, and other species inhabit the tropical seas. Tri- 

 chiurichthys, a fossil genus with well-developed scales, precedes 

 Trichiurus in the Miocene. 



The Palaeorhynchidse. The extinct family of Pal&orhynchidce 

 is found from the Eocene to the Oligocene. It contains very 



FIG. 210. Pakeorhynchus glarisianus Blainville. Oligocene. (After Woodward.) 



long and slender fishes, with long jaws and small teeth, the 

 dorsal fin long and continuous. The species resembles the 

 Escolar on the one hand and the sailfishes on the other, and 

 they may prove to be ancestral to the Istiophorida. Hemi- 

 rhynchus deshayesi with the upper jaw twice as long as the 

 lower, sword-like, occurs in the Eocene at Paris ; Palaorhynchum 

 glarisianum, with the jaws both elongate, the lower longest, is 

 in the Oligocene of Glarus. Several other species of both genera 

 are recorded. 



The Sailfishes: Istiophoridae. Remotely allied to the cutlass- 

 fishes and still nearer to the PalceorhynchidcB is the family of 

 sailfishes, Istiophorida, having the upper jaw prolonged into 



