This measurement was chosen over eye dia- 

 meter because the eyes tend to shrink in 

 preservative, and some had been lost. 



Premaxillary length: The distance from tip 

 to anterior edge of the mesethmoid, measured 

 along the dorsal profile of the snout. 



Upper and lower jaw lengths: The distance 

 from anteriormost tip to posterior edge of 

 maxillary and mandible. 



Body depth : Vertical distance immediately 

 behind the anus. 



Snout to anus distance: The straight-line 

 distance from anteriormost tip of snout to 

 posterior edge of anal opening. 



Snout to first and second dorsal fins: the 

 straight-line distance from anteriormost tip of 

 snout to origins of the fins. 



DEFINITION OF CERTAIN ADULT 

 CHARACTERS 



In the identification of larval and juvenile 

 fishes, it is important that the adult characters 

 be defined accurately because they are often ap- 

 plicable to the young as well. One useful skele- 



tal character for the diagnosis of adult scrom- 

 brids is the number of vertebrae. Previous 

 literature on the wahoo contains a wide varia- 

 tion in vertebral number, which is unusual in 

 the family Scombridae. The number of verte- 

 brae among most scombrids is known to be 

 nearly constant (Ford, 1937; Godsil and Byers, 

 1944; Clothier, 1950), but a number of reports 

 with descriptions of wahoo (table 2) give the 

 vertebral formula as 23 to 33 + 31 to 34 = 54 

 to 66 (precaudal vertebrae -^ caudal vertebrae 

 = total vertebrae) . 



I found that all papers published after 1923 

 which contained the formula 23 to 33 + 31 to 

 34 = 54 to 66 included Kishinouye (1923) as a 

 reference. Kishinouye (1908, 1915, 1923) did 

 not, however, discuss the wide range in number 

 of precaudal vertebrae, or refer to the seemingly 

 low count of 23 precaudals. It seems likely that 

 the 23 first reported by Kishinouye (1923) is a 

 typographical error and that 32 is the correct 

 number. 



Other evidence supports my suspicion that 

 the reported low count of 23 precaudal verte- 



Table 2. — Counts of some meristic characters of wahoo 



' FL (fork length): SL (standard length). 



■ From Liitken, 1880. 



^ Number of precaudal and total vertebrae as corrected. 



* From figure. 



= Last 2 flnlets fused. 



MORPHOLOGY AND DISTRIBUTION OF LARVAL WAHOO 



301 



