Fig. 1. (A) An illustration of the location of the sonic muscle in the weakfish Cynoscion regalis (modified from an illustration by H. L. Todd in Goode, 1884). (B) An oblique view of the swimbladder and associated sonic muscles; SM, sonic muscle; SB, lateral horn of the swimbladder; AP, aponeurosis overlying the dorsal surface of the swimbladder (modified from Ono and Poss, 1982). The swimbladder of a weakfish is approximately one-third of the total length of the fish, which ranged from 25 to 36 cm in our experiments. Figures taken from Connaughton et al. (1997).