Fishes of the JVestern North Atlantic 



113 



into abdominal cavity as a sort of blind sac, the two orifices rather close together. 

 Pyloric caeca numerous, short and branched, held together by connective tissue. 



Remarks. This genus is close to Megalops Lacepede, the oxeye herring represented 

 by M. cyprinoides of the Indian Ocean and adjacent Pacific, but it differs from Megalops 

 mainly in the more anterior position of the pelvic fins — well in advance of the dorsal 

 fin in Tarpon but inserted under the base of the dorsal in Megalops. Thus the dif- 

 ference is in the position of the pelvic fins rather than in the dorsal as stated in the 

 original description of Tarpon. Hollister, who compared specimens, has stated that 

 Tarpon has only 57 vertebrae whereas Megalops has 68, and that Tarpon has 12-15 

 dorsal rays whereas Megalops has 19-21 {42: 449). Also, Tarpon grows to a much 

 larger size. American ichthyologists generally have accepted Tarpon as a valid genus 

 while Old World students have rejected its separation from Megalops. Perhaps in con- 

 sideration of the additional differences now known, the separation may seem better 

 founded. Compared to Elops, Tarpons body is not as slender, its scales are larger, and 

 its dorsal and anal fins have long filaments attached to the last ray of each fin. 



Species and Range. A single species is known, ranging from Cape Cod, Massa- 

 chusetts, to southern Brazil. It has been reported also for tropical West Africa. 



Tarpon atlanticus (Cuvier and Valenciennes) 1846 



Tarpon, Tarpum, Sabalo Real, Cuffum, Silverfish, Silverking, Grand Ecaille, 



Jewfish, Palika 



Figure 19 



Study Material. A total of 25 specimens: 14, 78-1,175 mm TL (57-837 mm SL), 

 measured in the laboratory, from Boggy and Boca Grande, Florida; Fajardo, Puerto 

 Rico; "Cuba"; "West Indies"; and "Amazon River," Brazil; 11 adults, 100- 

 1,990 mm TL, from Gatun and Miraflores locks. Canal Zone, examined for food, sex, 

 and spawning condition. 



Distinctive Characters. See Remarks^ above. 



Description. Proportional dimensions in per cent of standard length, and counts, 

 based on at least 14 specimens in the Study Material unless stated otherwise, spec- 

 imens 57—837 mm SL. 



Body: depth 23.5-29. 

 Head: length 25—31. 

 Snout: length 4.5—6.2. 

 Eye: diameter 5.3—9.5. 

 Maxillary: length 1 5.5-1 8. 

 Anal fin: length of base 18-20. 

 Pectoral fin: length 19-22.8. 



Scales: 41—48 series. 



Gill rakers : 1 9—2 i + 36—40. 



Fin rays: dorsal 13—15; 



anal 22—25; pectoral 13 or 14. 

 Vertebrae: 53-57 (4 specimens). 



