ABSTRACT 



Leptocephalid forms of the ten-pounder, Elops saurus Linnaeus, 5.1 to 31.3 mm. in 

 standard length, were identified from plankton samples taken in waters off the 

 south Atlantic coast of the United States during May, October, and November, 

 1953. These forms represent a larval stage heretofore undescribed. A develop- 

 mental series was compiled from the plankton specimens and material obtained by 

 seine in beach and marsh waters in Georgia, representing the following periods or 

 stages of development: larval ( leptoeephalus, early metamorphic, mid-metamorphic, 

 and late metamorphic), juvenile, and adult. The series is illustrated and described; 

 and changes in form are discussed, in particular the shifting of the dorsal and anal 

 fins anteriorly during metamorphosis. Several early metamorphic larvae, reared 

 through metamorphosis in the laboratory, shrank in length from 35 mm. to about 20 

 mm. in 17-27 days. 



It is suggested that leptocephali occupy an offshore habitat and move into beach 

 and marsh waters when about 40-45 mm. long. The shrinking period (early 

 metamorphic) is spent in beach and marsh waters, and ends at about 25 mm. The 

 mid-metamorphic period (shrinking from 25 mm. down to 1S-20 mm. and subsequent 

 length increase to 25 mm.) is also spent in inshore waters. The late metamorphic 

 period ends, and the juvenile stage begins, at about 50-60 mm., when all fins have 

 full complements of rays, scales are present, the lateral line is formed, axillary 

 scales are present on paired fins, and subsequent developments are principally 

 changes in body proportions. This period is also spent in inshore waters. 



The occurrence of leptocephali in offshore plankton samples indicates offshore 

 spawning. No leptocephali have been reported from inshore waters. The length 

 of time spent in the leptocephalid period is unknown. The presence of "shrinking" 

 larvae in beach and marsh waters in Georgia from March to October suggests a 

 prolonged spawning season. 



