146 PHYSOSTOMI. 



Family, IV.— SCOMBRESOCIDjE. 



Pharyngognathi malacopterygii, Miiller. 



Pseudobranchise glandular, concealed. Margin of the upper jaw formed 

 mesially by the premaxillaries and laterally by the maxillaries. Barbels present 

 or absent. Lower pharyngeals united into a single bone. Dorsal fin rayed, 

 with or without Unlets posterior to it, situated opposite the anal, and in the 

 caudal portion of the vertebral column: no adipose dorsal. Scales present, 

 frequently a keeled row along either side of the free portion of the tail. Air- 

 bladder generally present, sometimes cellular internally, and destitute of a pervious 

 pneumatic duct. Stomach and intestines in an undivided tube. Pyloric 

 appendages present or absent. 



Synopsis of Genera. 



1. Belone. Both jaws elongated into a beak. No finlets. 



2. Scovibresox. Both jaws elongated into a beak ; finlets behind dorsal and 

 anal fins. 



3. Exoccetus. Jaws short. Pectoral fins elongated into organs for flying. 

 Among the fishes belonging to this family some are oviparous, others 



viviparous. 



The eggs of many have filaments springing from their outer covering, and 

 which enable numerous ova to adhere together in a mass, or attach themselves 

 to contiguous objects, preventing their subsiding into the mud. It has been 

 suggested that they are thus suspended so that by the ebb and flow of the tide 

 they may be constantly bathed by different water. Professor Hasckel observed 

 these filaments present in the eggs of gar-fish, Belone ; saury, Scombresox ; half- 

 beak, Hemiramphus, and flying-fishes, Exoccetus ; while Ryder has remarked on 

 having found similar filaments in one form of Atherinidoe, the Ghirostoma notata, 

 but in such they are only four in number, and situated close together. 



Genus I.— Belone, Cuvier. 



Mastacembelus (Klein) Bleeker ; Rhamphistoma, Rafin. ; Tylosurus, Cocco ; 

 Potamorrhaphis, Giinther. 



Branchiostegals numerous. Gill-openings wide. Body elongated, sub -cylindrical 

 or compressed. Byes lateral. The jaws prolonged into a bealc, the upper of which is 

 formed by the premaxillaries. Fine teeth {or rugosities) in both jaws, with a single 

 row of long, widely set conical ones ; palate toothed or toothless. The anterior dorsal 

 rays may or may not be elevated, forming a lobe to the fin, while the middle and 

 posterior ones may be short or elongated : no finlets : caudal usually forked. Scales 

 small. Lateral-line on free portion of the tail, with or without a keel. No pyloric 

 appendages. 



Cope considers that Belone should constitute a distinct family due to its 

 possessing distinct caracoid bones, and vertebrae with zygapophyses, a character 

 unusual among fishes (Proc. Amer. Phil. Soc. xvii, p. 695). Jordan and Gilbert 

 remark upon the absence of gill-rakers in Belone exilis and some other species 

 which it is proposed to unite into one genus Tylosurus, 



Geographical distribution. — Temperate and tropical seas ; some species resident 

 in fresh waters. 



Uses. — Indifferent as food ; all forms appear to possess green-bones. They are 

 very destructive among small fishes. 



