FISHES. 209 



** First dorsal with 4 stiff spines; body compressed; no lateral 

 band Mugilidce, the Mullets. 



FAMILIES OF HEMIBRANCHII. 



* Bones of head moderately produced ; ventral fins of a stout 



spine and a rudimentary ray ; dorsal preceded by free spines ; 



scaleless, naked or with bony plates; an oblong, silvery, 



* naked area in front of pectorals. . GASTEROSTEID^E, 98. 



** Bones of head much produced, forming a long tube which 



bears the short jaws at the end; ventral fins without spine. 

 f Body compressed ; no teeth ; scales small ; dorsal fins two ; 

 first with spines. . . Centriscidce, the Snipe Fishes. 

 ft Body greatly elongated ; teeth present ; no scales ; no dorsal 

 spines; middle rays of caudal produced into a long fila- 

 ment. . . . Fistulariidw, the Trumpet Fishes. 



FAMILIES OF SYNENTOGNATHI. 



* Jaws one or both elongated into a long beak. 



f Both jaws elongated; no finlets; size large. 



Belonidce, the Gar -Fishes. 



ft Lower jaw only elongate, or else dorsal and anal with 

 detached finlets, as in the Mackerels. 



Scomberesocidce, the Sauries. 



** Jaws moderate ; pectorals elongated, nearly as long as body, 

 used for " flying." . . Exocatidce, the Flying Fislies. 



FAMILIES OF HAPLOMI. 



* Snout depressed and elongated, its length more than half the 



greatest depth of body ; jaws, vomer, palate and tongue armed 

 with strong, hooked teeth ; body elongated, sub-terete ; size 

 large ; in fresh water ESOCH^E, 102. 



** Snout rounded and rather short, its length being less than half 

 the greatest depth of body ; teeth moderate ; size small. 



f Vent jugular, in front of pectorals ; eyes often undeveloped ; 

 ventrals small or wanting; cave fishes. AMBLYOPSID.E, 103. 



ft Vent normal : eyes present; ventrals well developed, 

 14 



