SAND BAR SHARK [Bigelow and Schroeder, 1948, p. 368.] [Garman,
1913, pl. 3, figs. 4-6 (as Carcharinus platyodon).] The brown
shark differs from the dusky (only member of its genus that
seems actually to have been taken within the Gulf) in the more
forward position and larger size of its first dorsal fin, in its
broader pectorals, and in its stouter trunk, heaviest forward
(compare specimens in figure 14). Also, the anterior edge of its
nostril is expanded as a low but definite triangular lobe, which
is not the case in the dusky shark. Other characters (in
combination) that mark it off from other members of this genus
that might stray to the Gulf are: Mid-line of the back with a
low ridge between the two dorsal fins; snout forward of a line
connecting the front margins of the nostrils, considerably
shorter than the distance between the nostrils; point of origin
of second dorsal fin about over origin of anal fin, its free
rear corner only a little longer than the height of the fin;
apex of first dorsal fin angu