Page:Life in Motion.djvu/202

182  the electric organ takes the place of the outer gill muscles of the fifth gill arch. In ordinary rays, and their distant cousins the sharks, these muscles are powerful organs for moving the lower jaw, but in the torpedo for

these muscles electric organs have been substituted. At an early stage in the development of the torpedo the tissue of the electric organ is like that of an embryonic muscle, showing numerous nuclei, and even a distinct longitudinal and a more faint transverse striation