THE TRUE FISHES. 181 
Dolphins (Coryphenidz).—The dolphins (Fig. 223) are 
large-headed pelagic fishes, tapering to the tail; the dorsal 
fin high, and extending nearly the entire length of the body. 
Fic. 223.—Flying-fish (Zxocetus) pursued by the dolphin. 
NotTre.—They are justly celebrated for their wondrous colors, that 
defy description, especially when dying, the various changes being due 
to the pressure of the convulsively contracted muscles on the chromato- 
phores or pigment-cells. 
Allied to them are the pompino and pilot-fishes (Vaz- 
crates). The latter are little fishes that resemble the blue- 
fish in shape, and accompany large fishes, several always 
being found with large sharks. 
Mackerel (Scoméber).—The mackerel is one of the 
most valuable of the food-fishes. They are from ten to 
eighteen inches in length, and richly ornamented with 
steel-blue and pearly tints. They run in schools, ranging 
