COMPARATIVE STUDY OF SCOMBROID FISHES. 
299 
dead. Tlie colour of tlie living fishes is, however, very difficult to observe, as 
they five rather in off-shore waters, swim very swiftly, and die soon after they 
are caught. A yellowish colour is found in mackerels and most tunnies, but 
is not found in fishes of the Cybiidæ, nor in bonitos. Moreover, this colour is 
not stable in specimens preserved in alcohol or formalin. 
Markings are mostly found on the back, and they are generally blackish. 
They are either irregular, waving streaks, dots, or longitudinal bands, and 
those found in the back are darker than the ground colour. Markings are 
sometimes found in the belly too, but they are sooty, fainter than those on 
the back, or are silvery in the sooty ground. The number of the markings 
corresponds generally with that of myotomes. Markings on both sides of the 
body are not strictly symmetrical. Colour and markings fade away in long 
preserved specimens. On the contrary markings invisible in fresh state may 
become visible after some days preservation in alcohol or formalin. Colour and 
markings of the immature forms differ greatly from those of the adult. 
Generally, immature fishes have simpler and less numerous markings than the 
adult ; but in the striped bonito immature fishes have more numerous stripes 
than the adult. 
Colour and markings become bright, when the fish is excited, and dull, or 
disappear when frightened. 
In our common mackerels pigments are found below the skin, and above 
the adipose layer, and in the skin which may easily Ire peeled off, scanty, 
insignificant pigment-spots only are found. This explains the reason why stale 
mackerel often retain brilliant colours. In Bastrelliger chrysozonits we find a 
row of dark spots on each side of the base of the dorsal fin, besides two dark 
longitudinal bands in the back. Two bands below these dark bands and 
running Ireland the pectoral are yellowish. The yellowish colour gradually 
fades in preserved specimens. 
Seerfishes have generally two or more rows of dark roundish spots near 
the lateral median line of the body. In C ybiura nipJionium (fig. 32) we 
sometimes find the whole body except the back densely covered with spots. In 
the same species the ventral median line, and a longitudinal hue running 
backward from the base of each pectoral are sometimes coloured black. Cybium 
cornmerson (fig. 39) and Acanthocybium solandri (fig. 31) have many transverse 
