COMPARATIVE STUDY OF SCOMBROID FISHES. 
301 
we peel off the skin, the colouring is mostly lost, and only a thin pale layer 
of pigment is found above the adipose layer of the body. Sometimes the 
belly of bonitos is sooty brown. Fishermen believe that such fishes remained 
on the muddy bottom a long time. In a small specimen of Katsuivonus 
pelarnis, ca. 20 cm long, I found 5 faint transverse bands near the lateral 
medium line, besides the longitudinal bands. These transverse bands are 
called by fishermen bands of the saurel-type, and when these bands appear 
on the side of the fish, they are greatly excited to bite so that we can 
anticipate a great catch. In immature bonitos ca 30 cm long, longitudinal 
bands are more numerous than in the adult, the auxiliary bands being found 
near the lateral median hue. In immature specimens of Euthijnnus yaito, ca 
13 cm long, we find about eight transverse bands, crossing down the lateral 
line. These bands are darker and bend a little backward at the dorsal part 
above the lateral line. In a specimen ca 19 cm long there are about thirteen 
transverse bands. The course of the dorsal part of the bands above the 
lateral line now nearly coincides with the boundary line between myotonies. 
Specimens of such size have one to three dark spots at the pectoral region. 
The spinous dorsal, caudal, and the axial side of the pectorals are generally 
blackish. Ventrals and the anal are pale coloured or nearly colourless. In 
the Cybiidæ the spinous dorsal is generally black, but in immature forms of 
some seerfishes it is colourless at the posterior portion. In Gymnosarda (fig. 
37) the tip of the second dorsal and the anal is colourless. In the Plecostei 
the first dorsal is washed with black at the margin. It is remarkable that fins 
are more or less yellowish in tunnies ; but that colour never appears in the 
fins of seerfishes and bonitos. The yellow colour is especially conspicuous in 
Parathunnus mebacJd and Neothunnus macropierus ; but not conspicuous in 
Thumnus gerrno and Neothunnus rarus. 
Head. 
Generally speaking the head is large, one fifth of the total length of the 
body in the Scombridse, one sixth in the Cybiidæ, and one fourth in the 
Plecostei. The length of the head is generally more or less longer than the 
height of the body, even in the case of tunnies and bonitos. Therefore it is 
very remarkable that the head of Gybiurn korecinum is 1|- times the height 
