COMPENDIUM OF GENERIC DISTINCTIONS. 



783 



Genwt. GAD US. Head smooth. Teeth conical, in inter- | 

 maxillaries, vomer, and lower jaw. Three dorsals. Bran- 

 chiostegais seven. Ventrals under throat and pointed. A 

 barbule on the chin. Colder seas. (Including Morrhua.) 



Genus. MERLANGUS. As Gadus, but no barbule. Many 

 seas. 



Genus. MERLUCIUS. Two dorsals, one long anal. No 

 barbule. 



Sub-order. APODES. No ventrals. Body long and 

 snake-like ; skin thick and soft ; often with minute scales 

 hidden in skin. 



Family. OPHIDINI. Swimming-bladder either closed 

 or wanting. 



Genus. AMMODYTES. Body long, with minute scales. 

 Lower jaw longer than upper. Teeth none. Branchiostegais 

 seven. Dorsal and anal very long, tail-fin forked. Many 

 seas. 



Family. ANGTIILLID5!. Teeth comb-like. Gill-open- 

 ings on sides. Pectoral fins conspicuous, dorsal and anal 

 running round tail. 



Genus. ANGUILLA. Head and tail blunted. Seas and 

 rivers. 



Family. CONGERIDJB. Dorsal commencing close to 

 head ; skin without scales. 



Genus. CONGER. Front nostrils in short tubes at end of 

 snout. Teeth of palate and vomer in straight, chisel-shaped 

 rows. Many seas. 



Family. M TIK2ENID J. No pectorals ; gill-openings only 

 narrow slits. 



Genus. MURJENA. Single row of teeth on nasal bone. 

 Many seas. 



Family. GYMNOTIDJE. No dorsal ; anal very long. 

 Genus. GYMNOTUS. Scales none. 



Family. LEPTOCEPHALID51. Small, scaleless, very 

 much compressed, and transparent. Lateral line formed by 

 intersection of muscles. Many seas. 



Genus. HYOPROBUS. Jaws long, straight ; body deep 

 behind head. Tail pointed. 



Genus. TILURUS. Membranous dorsal beginning at 

 head. Anal none. Pointed teeth in both jaws. Tail very 

 long. 



Genus. LEPTOCEPHALUS. Muscular bands bent regu- 

 larly forward. Tail moderate. 



Sub-order. ABDOMINALES. Ventrals on abdomen and 

 behind pectorals, sometimes absent. Swimming-bladder in 

 most, and with an air-duct. 



Family. HETEROPYGID.2E. Ventrals small. Dorsal 

 set far back. Gill-apertures small. Body scaled. Teeth 

 small and sharp in palate, none on vomer or tongue. 

 Branchiostegais seven. Eyes none external. 



Genus. AMBLYOPSIS. As family. North America. 



Family. CLUPEIDJE. Fatty dorsal wanting. Body 

 with distinct and mostly large scales. Two inferior pha- 

 ryngeal bones. 



Genus. ENGRAULIS. Head pointed, upper jaw longest, 

 gape very deep. Ventrals before dorsal. Branchiostegais 

 twelve. Many seas. 



Genus. CLUPEA. -Body compressed, scales loose and 

 /arge. Teeth minute or wanting. One dorsal. Abdomen 

 keeled. Many seas. 



Family. ESOCID1E. Dorsal fin set far back, near tail- 

 fin. Edge of upper jaw partly formed by intermaxillary 

 bone. 



Genus. Exoc^TUS. Pectorals large and very long, used 

 for flight. Lower lobe of tail-fin elongated. No teeth on 

 palate. Warm seas. 



Genus. HEMIRAMPHUB. Lower jaw long and projecting. 

 Teeth small and placed in a bolt round each jaw, none oo 

 Body much elongated. Pacific. 



Genus. BELONE. Both jaws much lengthened and 

 slender, lower longer than upper. Teeth small hi both jaws, 

 of unequal sizes. Many seas. 



Genus. Esox. Body rather loiig ; snout flattened, 

 Mouth, jaws, and palate, crowded with sharp teeth. Fresh 

 waters. 



Family. SALMONID2E. Second dorsil of a fatty con- 

 sistence, without rays. 



Genus. SALMO. Head smooth. Teeth on vomer ; pala- 

 tino and maxillary bones. Branchiostegais often xinequal 

 on the two sides. Seas and fresh waters. 



Genus. SCOPELUS. Teeth sharp and conical in both 

 jaws. Branchiostegais nine. Palatine teeth very small. 

 Many seas. 



Genus. SERRASALMUB. Teeth in both jaws, triangular, 

 flat, sharp-edged, mostly in a single line. Body rathei 

 compressed. Abdominal line serrated. Kivers of South 

 America. 



Family. CYPRINIDONTID.E. Jaw-teeth very small. 

 Throat crowded with teeth. Branchiostegais five six. 

 Whole of head scaled. No fatty fin. 



Genus. ANABLEPS. Teeth on palate. Cornea of eye 

 divided transversely. Head flattened between eyes. Nos- 

 trils in short tube. Surinam. 



Family. CTPRINIDJE. Body with rounded scales. One 

 rayed dorsal. Mouth small and toothless. Inferior pha- 

 ryngeal bones with large teeth. Branchiostegais three. 



Genus. CYPRINUS. Head naked. Branchiostegais flat 

 and broad. Anal fin short. Fresh waters. 



Genus. TINCA. Dorsal and anal fins short. Barbules 

 very small. Scales small. Ponds and rivers. 



Genus. ABRAMIS. No barbules. Body deep and com- 

 pressed. Base of anal long. Lakes and rivers. 



Genus. LEUCISCDS. Dorsal and anal short. Barbules 

 none. Fresh waters. 



Family. SILURID^E. Body naked or shielded. Inmost 

 \he first ray of dorsal and pectoral a spine with moveable 

 joint. 



Genus. SlLURUS. Body naked. Teeth very numerous. 

 Dorsal small, single near head. Anal long. Barbules foui 

 to six, some very long. Seas and rivers. 



Order. PECTOGNATHI. Upper jaw-bones immovo- 

 ably joined to sides of intermaxillaries. Body with shieldi 



Family. SCLERODERMI. Snout conical or pyramidal. 

 Mouth toothed, in front of snout. Body with hard scales 

 or cuirassed. 



Genus. OSTRACION. Teeth ten to twelve in each jaw. 

 Body tri- or quadrangular, cuirassed, with holes for tail, 

 fins, and mouth. Tropical seas. 



Genus. BALISTES. Body compressed. Eight teeth in 

 each jaw. First dorsal formed of one or several spines. 

 Second dorsal near tail, soft. Tropical seas. 



Family. GYMNODONTES. Jaws projecting from mouth, 

 covered with solid tooth-ivory. 



Genus. DlODON. Jaws not divided. Warm seas. 

 Genus. TRIODON . Upper jaw divided. Warm seas. 

 Genus. TETRODON. Both jaws divided. Warm seas. 



Genus. ORTHRAGORISCUS. Body very short, deep, and 

 compressed. Jaws not divided. Dorsal and anals connected 

 with tail-fin. Many seas. 



Order. LOPHOBRANCHIATA Gills composed of 

 small round tufts, the operculum very large and the aper- 

 ture very small. Body covered with bony rings. 



