COMPARATIVE STUDY OF SCOMBROID FISHES. 
329 
Scomber japonicus Cybiim niphonium Thunnus orientalis Katsuwonus pelamis 
Fig. F. Dorsal view of the branchial arches, and the side view of a detached gill-raker. 
branchial arches do not reach the dorsal margin of basibranchials, so that the 
upper margin of the basibranchials is higher than that of the branchial arches. 
In Scomber japonicus the first basibranchial is nearly so short as the second, 
and is bent a little downward. In Bastrelliger chrysozonus the first basibranchial 
is the longest, straight at the dorsal margin, while the second and third are 
short and nearly equal in length. The third ossicle is bent downward at the 
posterior half. In the Cybiidæ the grooves for the attachment of branchial 
arches reach the dorsal margin of the basibranchials. The anterior end of the 
first basibranchial is more or less thickened. The second is bent downward 
at the middle. In the Thunnidæ the groove for the attachment of branchial 
arches are very deep and reach the dorsal margin of the basibranchials. 
The third basibranchial is horizontally flattened. In the Katsuwonidæ the 
basibranchials are laterally compressed and narrow. The anterior half of the 
first basibranchial ascends, and the third is bent downward near the posterior 
end. 
The branchial arches are armed with villous teeth, densely growing on 
