298 
KAMAKICHI KISHINOUYE : 
form of the body differs sometimes in different seasons. Generally the form of 
the body is fat and fine before the spawning season ; but it 1 »comes lean and 
ugly after spawning, and remains in such a condition during some three or 
four months. The lean form of Cybiurn niphonium in summer is especially 
remarkable. This difference of fatness in seasons is little discernible in the 
case of the Plecostei. In the striped bonito, however, the flesh becomes 
remarkably watery after spawning, much paler in colour, and at the same 
time losing both taste and tenacity. 
Size of the Body. 
Mackerels are generally small, never reaching one metre in the total 
length. Seerfishes generali}’ grow more than a metre in length, and certain 
species attain a very large size, for example Cybiurn chmense grows to a length 
of more than two metres, and to a weight of more tlian one hundred kg. 
Gyrnnosarda nuda, Cybiurn cornrnerson and Acanthocybiurn solandri grow very 
large too. Much larger sizes are rather common in tunnies. Thunnus orientalis 
grows to more than 260 kg in weight, and ca 3 m in length, and even tunnies of 
375 kg are recorded. Thus our common tunny is smaller than the Atlantic 
congener, the latter is said to grow to ca 451 kg in weight. Neothunnus rarus 
is the smallest tunny known, reaching maturity when it is ca 60 cm in length, 
and 8 kg in weight, being nearly equal to the average size of the striped 
bonito. In bonitos the size liecomes small again, rarely exceeding a metre in 
length, and 15 kg in weight, the smallest fish of the kind is found in the 
genus Auxis. Fishes of the genus Auxis are ca 30 cm long and 600 g in 
weight. 
Colour and Markings. 
The back is blackish at the anterior part, changing gradually to bluish 
or greenish colour, with metallic lustre, and the belly is silvery < r greyish, with 
irridescent reflections. Generally speaking the ground colour of the back is 
greenish in the Scombridæ, steel-blue in the Cybiidæ, and bluish in the 
Plecostei. When we observe the living fish, the colour greatly differs from that 
of the dead, even recently killed. I have observed a remarkable difference in 
the genus Auxis, which is dark bluish green when living, but bluish when 
