_Specific characters._—Form elongated, high and narrow, the head wider than the thickest part of body. Length of snout equal to diameter of eye, lower jaw very slightly longest. Total length a little more than four and a half times that of head, which is equal to the greatest height of body. Head moderately arched, rounded above, the width between eyes a little less than the width of orbit. Orbit circular, contained four and a half times in length of head. Anterior lobe of dorsal commencing just behind head, triangular, one-twentieth of the length of fin, equal to the middle lobe in height; middle lobe gradually arched, its spines more slender than those of the first lobe; posterior lobe with soft rays only, about equal to the first, in size and form, extending nearly to the tail. Caudal fin quadrangular, its end obtusely truncate, nearly twice as long as wide. Anal commencing opposite seventeenth dorsal spine, nearly straight, its height one-fifth its length, and ending a little anterior to end of dorsal. Ventrals narrow, the middle ray longest. Pectorals arising opposite third dorsal spine, nearly as wide as long. D. V-xxvii to xxx-8; C. 5-5; A. 26 to 28; V. 3; P. 11. Scales in about 250 rows along middle of side, in 18/50-18/18 vertical rows along lateral line. Proportional measurements: Length of largest specimen, 4 in. 100. Length of head .20 Height of pectoral .15 Length of dorsal .72 Length of caudal .12 Length of anal .44 Height of ventral .09 Height of body .22 Width of body .08 _Colors._—Exceedingly variable, but the general pattern, as preserved in alcohol, consists of a series of vertical bands, alternating with spots of various shapes and sizes, and often densely mottled with dark and light blotches distributed regularly, but not describable. The fins have alternating bands, and in all the specimens the membrane between the third and fourth dorsal spine is as clear as glass, as if intended to be seen through, but probably shines in the water as a sort of signal. When fresh the colors of those from San Diego were as follows: 1st, dark brown, a purple lateral stripe, sides with dark and light brown bars, having silvery blotches between them; below yellowish, top and sides of head blotched with yellow, a bright red ring with a green centre near pectorals, and another near caudal. Dorsal with alternating bars of olive and yellow; pectoral yellow at base, its rays reddish, barred with purple, ventrals and anal smoky.