POTTHOFF: DEVELOPMENT AND STRUCTURE OF FINS IN CORYPHAENA 



C. hippurus at 17.2-30 mm SL. The development of 

 individual anal fin pterygiophores was similar to 

 that of the dorsal fin pterygiophores. 



Each anal fin pterygiophore of both species had 

 two rays; one ray was in a serial association and 

 the preceding ray was in a secondary association. 

 The posteriormost anal ray lacked a secondary 

 association with a pterygiophore and the anterior- 

 most anal ray lacked a serial association (Figure 

 16). Exceptions were common with the anterior- 

 most pterygiophore and rays. Many specimens of 

 both species had very small first pterygiophores or 

 even vestiges. In a few instances in both species 

 the anteriormost first pterygiophore was com- 

 pletely or partially fused to the second pterygio- 

 phore. The normal number of anal rays associated 

 with the first pterygiophore was two, but for both 

 species one or three rays also were found. The 

 anteriormost anal ray was either normal as in 

 Figure 16, very small, or a vestige. As in the dorsal 

 fin, the vestige was either single left or right, 

 or paired. 



A distal radial was present between the base of 

 each fin ray almost for the entire anal fin. It 

 developed and ossified from the pterygiophore 

 cartilage. Only the anteriormost anal fin ray 

 sometimes did not have a distal radial between its 

 base (Table 7). Only 1 C. hippurus out of 49 had 

 two anteriormost rays without distal radials. 

 When the anteriormost ray had a distal radial, it 

 was either serially or secondarily associated with 

 the first pterygiophore. When the association was 

 serial, the anteriormost pterygiophore had only 

 one ray; when it was secondary, it had two rays. It 

 is possible that, when the association was sec- 

 ondary, the distal radial of the first fin ray was in 

 actuality a vestigial pterygiophore. The specimen 

 in Figure 16 did not have a distal radial for the 

 anteriormost ray. The absence or presence of 

 distal radials for the anteriormost anal fin ray was 

 not related to the number of fin rays that were 



Table 7. — Number (adult count) of anteriormost anal fin rays 

 without distal radials and number of anal fin rays associated 

 secondarily and serially with the anteriormost anal fin pterygio- 

 phore in 49 Coryphaena hippurus (41.0-176 mm SL) and 33 

 C. equiselis (74.1-172, 314 mm SL). 



Number of anterior- 

 most anal fin rays 



293 



