COMPARATIVE STUDY OF SCOMBROID FISHES. 
347 
epaxial and liypaxial portions lias some breadth in the Scombridae and Cybiidae 
(fig. 6), therefore we find two parallel traces of connective-tissue fibres, which 
connect firmly with the vertical aponeurosis, ensheathing the axial skeleton 
from both sides of it, just at the end of the neural and haemal processes, 
where the myotonies are very sharply bent. In the Plecostei, however, myotonies 
are very thin at the points of external bending and they are inserted to the 
axial skeleton at one line of traces. In Cybium the number of cones of 
myotonies in cross-section of the lateral muscle is only a little more numerous 
than in Scomber , but in Sarda the number is almost as many as in the 
Thunnidae. At the anterior end of the body the apex of the cones is nearer 
the axis than to the surface of the body ; but in the caudal portion it gradually 
approaches the surface. In the Katsuwonidae (fig. 19) a paid of some anterior 
myotomes envelopes a large tendinous chord from the second vertebra, or rather 
a part of some anterior myotomes forms a small auxiliary cone of concentric 
myotomes, which ends in a strong tendon attached to the second vertebra. 
In Evthynnus and Auxis another smaller auxiliary cone of myotomes round a 
tendon is inserted into the supraclavicle (fig. 2). 
In the Scombridae and Cybiidae and also in the Katsuwonidae the dorsal 
and ventral limbs of the myotome are more or less wide at the insertion into 
the median septum ; but in the Thunnidae the dorsal and ventral limbs of the 
myotome are very thin. 
The dorsal limb of some anterior myotomes always reaches the front margin 
of the frontals in the Plecostei, but in the Teleostei it is not always the case. 
In fishes the median superficial lateral muscle is generally darker in 
colour. Its extent is sometimes very well defined, but sometimes more or less 
indistinct. It is thin and narrow at the anterior paid, but thick and wide at 
the posterior. This dark coloured portion is triangular in cross-section, and is 
bounded by membranes of connective tissue, which are united to the line 
connecting the distal end of intermuscular bones. In the Teleostei tendons of 
the great lateral muscle are mostly found in the superficial dark coloured 
portion ; but in the Plecostei they are found in deeply seated dark coloured 
muscles. The deeply seated dark red portion of the lateral muscle is charac¬ 
teristic to the Plecostei. It is called “ chiai ” or “ chimi ” in our country, from 
very old times. In 1712 Ryonan Tebajima described “ chiai ” as being found 
