THE NOT ACANTHI, 107 



fin is always wanting ; the caudal fin is usually directed upward. All the species frequent deep 

 seas. Three genera have been defined. The genus Trachypterus, which has well-developed ventral 

 fins, is represented by many species on the Mediterranean coasts of Europe, and also occurs on the 

 west coast of South America. In British waters it is represented by the Deal-fish (Trachypterus 

 arcticus), which ranges northward to Iceland and Norway. Large specimens are six feet long 

 and one foot high. Its body is very tender and brittle, so that it is rarely preserved. Its 

 movements are slow, and resemble those of the Flat-fish. They are said when alive to be fat, 

 with the sides of the body round. The sides ai-e silvery, the high dorsal fin is red, and the caudal 

 fin, which is directed upwards like a cock's tail, is also red. The genus Stylophorus, found in the 

 Gulf of Mexico, has the tail terminated in an appendage like a cord, which is twice as long as 

 the fish's body. The genus Regalecus has each ventral fin reduced to one long filament, and 

 the caudal fin is usually absent or represented by a rudiment. Two species occur in the 

 Mediterranean, two on the coast of Norway, while one, known as the Ribbon-fish, or Oar-fish 

 (Regalecus banksii), occurs in British seas. A specimen was taken in Yorkshire twenty-four- 

 feet long, though the usual length is about twelve feet. The colour is silvery, with irregular dark 

 lines and spots on the anterior part of the body. The dorsal fin is red, but there is no trace of a 

 caudal fin. The anterior twelve spines form an elevated crest behind the head. The lateral line is. 

 marked on the lower third of the body by elongated flat scales, but the skin generally is covered 

 over with small bony tubercles. The snout is truncated, and there are no teeth in the mouth. The 

 stomach is prolonged as a pouch, which reaches between the muscles to near the end of the tail. A 

 specimen measuring fifteen feet and a half in length was one foot two inches deep, three inches 

 and a half thick, and weighed 182 Ibs. 



The twentieth and last division of Acanthopterygian fishes is formed for 



FAMILY LV. THE NOTACANTHI. 



This family includes the species of the genus Notacanthus. This group is characterised by 

 having the dorsal fin represented by short free spines, the soft portion being sometimes entirely 

 absent. The snout protrudes beyond the mouth. Species occur in the Mediterranean, Arctic 

 regions, and in the Australian seas. The Notacantlms rissoanus, which has the nasal region prolonged 

 into a proboscis, and has thirty or more spinous finlets on the back, is regarded by Dr. Gunther as 

 likely to form the type of a second genus. 



CHAPTER VI. 

 THE ORDER PHYSOSTOMI. 



ORDER PHYSOSTOMI SiLURiix*:-Characters The Various Sub-Families The Silurus glanis The Malapterurus 

 electricus Its Electric Organ The Genus Loricaria Curious Feature connected with the Genus Aspredo 

 CHARACINID.E HAPLOCHITONID.E STERNOPTYCHID.E Pearl-spotted Fishes SCOPELID.E Bombay Duck STOMIATID.E 

 SALMONID.E Characters THE SALMON Description Climbing the Rivers The "Leaps" Changed Appearance 

 after Spawning Hatching The Fry Growth-Stages of the Young The Journey to the Sea The Salmon at Sea- 

 Various Modes of Fishing Largest Catches Distribution THE GREY TROUT THE SALMON TROUT THE COMMON 

 TROUT THE GREAT LAKE TROUT Other Species of Trout THE CHARR Various Species THE SMELT THE CAPELAN 

 The Genus Coregonus THE POLLAN THE GRAYLING PERCOPSID.E GALAXID.E Mo RMYRID.E GTMNARCHID^E 

 ESOCID.E THE PIKE Its Size and Age Its Voracity Pike Migrations The Lucie Family Characters of the Fish 

 UMBRiDvE SCOMBRESOCID.E The Genus Belone-The Garfish -The Genus Scombresox The Saury, or Skipper 

 The Genus Hemirhamphus The Flying Fish The Genus Exocatus Characters Height and Duration of Flight 

 CYPRINODONTID.E- Singular Eye Character of Anableps HETEROPYGII CYPRINID.E Distinctive Features The Carp 

 Habits Can) Culture -Its Diet-The Crucian Carp THE GOLD FISH Kept as a Pet Variation in Colour 

 Characters-The Barbel- The Gudgeon-The Roach-The Chub-The Dace The Ide-The Red-eye, or Rudd The 

 Minnow The Red-fin The Spawn-eater The Tench The Rhodeus amarus The Bream-The Bleak The "Essence 

 de 1'Orient "The Loach-The Spinous Loach. 



ORDER VI. PHYSOSTOMI, OR FISHES WITH THE AIR-BLADDER OPENING 



INTO THE MOUTH. 



THE Physostomi form a large division of fishes characterised by having the fin rays jointed. 

 Sometimes, however, the first ray in the dorsal fin and in the pectoral fin are more strongly developed 



