57. SCOMBERESOCID^. 371 



OKDER Q.-SYNENTOGNATHI. 



(The Synentognathous Fishes.} 



Lower pharyugeal bones fully united ; second and third superior pha- 

 ryugeals much enlarged, oval, not articulated to the cranium, sending 

 processes forwards ; the fourth wanting. Ventral fins abdominal, without 

 spiue, the rays more than 5. Scapula suspended to the cranium by a 

 post-temporal bone, which is slender and furcate. Parietal bone much 

 reduced. Supraclavicle not distinct; no interclavicle. Basis of cranium 

 double in front, but without muscular tube. Fins without spines. Air- 

 bladder usually large, without pneumatic duct. This order includes 

 only the family of Scomberesocidce, and marks the transition from the 

 Physostomi to the Acanthopteri. Its relations with the Haplomi are very 

 intimate. (<row, together; e^roc, within; pa0?, jaw.) 



(Physostomi pt. family Scomberesocidce Giinther, vi, 233 



FAMILY LVIL SCOMBERESOCIM1. 



(The Gar-fislies and Flying-fishes.) 



Body oblong or elongate, covered with cycloid scales, which are usu- 

 ally deciduous. Lateral line running very low, along the sides of the 

 belly. Head more or less scaly, usually with vertical sides. Mouth 

 various, the jaws being often prolonged into a beak. Premaxillaries not 

 protractile, hinged at base mesially; margin of the upper jaw chiefly 

 formed by the premaxillaries ; the short maxillaries often entering the 

 lateral margin ; maxillary often anchyclosed with the premaxillary ; its 

 edge slipping under the front of the preorbital. Dentition various. 

 Dorsal fin without spines, inserted on the posterior part of the body, 

 opposite the anal and usually similar to it. Ventral s abdominal, of sev- 

 eral soft rays, usually inserted posteriorly. No adipose fin. Pectoral 

 fin inserted high, sometimes used as an organ of flight. Caudal fin 

 usually forked, the lower lobe the longer. Vent close in front of anal. 

 Nostrils large, double, near the eye. Lower pharyngeals fully united. 

 Gill-membranes not united, free from the isthmus. Pseudobranchise 

 hidden, glandular. Gill-rakers various. Gills 4, a slit behind the 

 fourth. Air-bladder usually large, sometimes cellular. Intestinal canal 

 usually simple, without coaca. Carnivorous. One genus (Zenarchop- 



