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KAMAKICHI KISHINOUYE : 
Thunnus orientalis Euthynnus yaito 
Eig. G. Dorsal, lateral, and ventral views of the basibranchials. 
small calcareous pieces on these arches. In the Scombridæ the upper, anterior 
part of the basibranchial ridge is almost naked, being protected with a few 
calcareous dentigerous pieces. The villous teeth on the pharyngeal bones are 
nearly equal to those on the branchial arches, contrastiDg to the coarser teeth 
on the former in the other scombroid fishes. • In the Cybiidæ dentigerous pieces 
are arranged in two rows, meeting at the dorsal median line of the branchial 
arch. In the Plecostei two rows of dentigerous pieces meet near the internal 
comer of the branchial arch. 
The hypobranchials are short, joined to the sides of the second and third 
basibranchials, and are grooved on the outer or ventral side. They are not 
found in the fourth arch. 
