454 
KàMAKICHI KISHINOUYE: 
mass like a rod with the plexus of arterioles from the dorsal aorta to the 
vertical of the ninth vertebra ; but anterior to the vertebra the plexus is 
discontinued and is divided only into small bundles of venules. 
Kidneys are much elongated posteriorly. In the haemal canal, below the 
vertebral column, there is also a renal body. 
The back is dark bluish violet, with some transverse light coloured 
markings, the sides are silvery with four or more dark coloured longitudinal 
bands on each side. Dorsals, dorsal finlets, pectorals, and the anal are dusky. 
Iris silvery, with a greenish shade. 
The bonito lives in the clear blue water of the Kuroshiwo, 20-30° in 
temperature, and 1.024-1.026 in specific gravity. On the Japan Sea, this fish 
is caught in small numbers, late in autumn or in winter only, there being no 
special fishing for this fish. On the northeastern coast of Hondo, the bonito 
is generally caught in grounds very far from the land, 100-200 miles off. In 
spring bonitos begin to migrate northward, and reach the ground off the 
southeastern coast of Hokkaido in summer. Sometimes the fish makes big 
shoals of several hundreds to thousands, and when they attack a school 
of small fishes, such as sardines and anchovies, they surround the latter 
till the victims form a dense spherical mass. Then the bonitos feed gradually 
on the stragglers from the school, swimming around outside the mass. 
Generally they feed on the medium sized plankton :—amphipods, Squilld s 
larvae and other crustaceans, pteropods, heteropods (chiefly Atlanta), 
calamaries, and immature or small fishes, etc. According to experienced 
fishermen, bonitos are said to contain plenty of food in their stomach, when 
they are caught in large quantities with rods and lines ; but almost no trace 
of food is found in their stomachs, when refuse to bite a hook. This 
is true also of the tunny fishery by means of long lines. Though bonitos and 
tunnies are very voracious and bite a hook easily and eagerly, especially when 
they are in a frenzy of competition to get as much food as possible, yet they 
are cool and cautious when there is only a little food. And in midsummer 
when the reproductive elements become ripe, bonitos seem to fast. In the 
water round Ryukyu and the adjacent islands we find small bonitos about 20 cm 
iu length in August, and in January I have obtained small bonitos ca. 30 cm 
(without caudal) from the stomach of tunnies, caught near the Ogasawara 
