112 Memoir Sears Foundation for Marine Research 



The young pass through a leptocephalus stage, similar to that of the eels. 

 Range. The members of this family are widely distributed in the warmer seas. 



Key to Western Atlantic Genera 



I a. Body moderately deep, rather strongly compressed laterally; mouth superior, with 

 tip of mandible entering dorsal profile; last ray of dorsal and anal produced, fila- 

 mentous; scales large, about 41—48 in a lateral series; anal with about 22—25 rays. 



Tarpon Jordan and Evermann 1896, below. 



lb. Body very slender, not greatly compressed laterally; mouth terminal or nearly 

 so; last ray of dorsal and anal not produced into a filament; scales small, 

 generally more than 100 in a lateral series in American species; anal with fewer 

 than 20 rays. Elops Linnaeus 1766, p. 123. 



Genus Tarpon Jordan and Evermann 1896 

 Tarpon 



Tarpon Jordan and Evermann, Bull. U.S. nat. Mus., 47 (l), 1896: 409; type species by original designation, 

 Megalops atlanticus Cuvier and Valenciennes, Hist. Nat. Poiss., Jp, 1846: 398. 



Generic Synonyms: 



Clupea Block, Naturg. ausland. Fische, Pt. 9, 1794: 32; in part, for C. cyprinoides Bloch; Shaw, Genl. Zool., 



5(1), 1804: 173, for C.gigantea Shaw. 

 Megalops Lacepede, Hist. Nat. Poiss., 5, 1803: 289; in part, for M. giganteus Voigt in Cuvier, Das Thierreich 



(German transl.), 2, 1832: 423. 



Characters? Body oblong, rather strongly compressed. Vertebrae about i,c^. 

 PsEUDOBRANCHiAE undcvclopcd. Branchiostegals about 23. Mouth quite oblique, 

 superior, with prominently projecting mandible. Lateral line decurved, with branched 

 tubes. Scales large, not especially primitive, their characters similar to those of Elops 

 (cf, Cockerell, ly. 122); scales extending somewhat onto base of anal and caudal but 

 not onto dorsal. Dorsal fin high anteriorly, its last ray produced and filamentous. Anal 

 similar to dorsal but longer, its last ray produced in large examples, its origin not far 

 behind dorsal base. Pelvics inserted well in advance of dorsal fin. Last several Verte- 

 brae clearly out of line with main axis, being directed toward the tip of upper lobe of 

 caudal. Air bladder large and opening into gullet; within bladder a considerable 

 amount of cellular, lung-like tissue; two large and two small strands adhering to bladder 

 wall (bladder serving somewhat as an air-breathing organ, much as in gars [pp. 64, 

 67]; for description and figures of the modified bladder, see Babcock, i [1936]: 50). 

 Alimentary canal much shorter than body; the stomach large, reaching far back 



3. The skull has been fully described and figured by Gregory, who regarded it as a little less primitive than that of 

 Elops {30: 137-142, figs. 31-33). The characters of the tail of Tarpon and related genera have been described by 

 Regan {sg: 354), and in more detail by HoUister (39: 264). 



