HAMMERHEAD SHARKS — GILBERT 



57 



Sphyrna media also differs from S. corona in having: The anal fin 

 more deeply falcate and with a more pointed apex (figs. 14a, 15a); 

 anterior-median pore patch on underside of head with the posterior 

 margin more broadly rounded and with a pointed median-posterior 

 extension (fig. 22/) ; a more pointed upper precaudal pit in smaller 

 specimens (fig. 21 g); and a slightly wider mouth. When the trans- 

 verse distance between the corners of the mouth is divided by the 

 head width, the values obtained are somewhat greater for S. media 

 Finally, Sphyrna media may be a larger species. The largest specimen 

 of Sphyrna media seen (a head) was calculated to be 1025 mm. TL, 

 while of the 17 specimens of Sphyrna corona examined, the largest 

 (the holotype) measured only 672 mm. More specimens of S. corona 

 must be seen to definitely confirm this, however. 



A comparison of Sphyrna media with other members of the genus is 

 presented in table 1. 



Description.^ — -Meristic data appear in table 7. Characters men- 

 tioned in the diagnoses of the subgenus Platysqualus and of S. media 

 are not repeated here. 



Figure IS. — Sphyrna media: a, juvenile female, 356 mm. TL, from Chiapas, Mexico (FMNH 

 63093); b, head of same specimen. (Drawings by Paul Laessle.) 



Head moderately expanded, the greatest width measuring from 

 22.3 to 27.3 percent of TL; character of anterior-median margin of 

 head somewhat variable, evenly rounded in some individuals, with no 

 median indentation, and with a broad, very shallow median depres- 

 sion in others; outer posterior corner of lateral expansion of head 

 situated anterior to corner of mouth; narial flap broad, bluntly pointed 

 at tip, with the broadly curved outer edge curving sharply inward; a 



