COMr.\n\TIVK silDV OF SOWIBHOID FLSIIKS. 



329 





Scomber japonicus Oyhium niphonivm Thunnus orientalis Kutsuwonus pelamis 



Fig. F. Dorsal view of the branchial arches, and the siile view of a detached gill-raker. 



brancbiftl arches do not reach the doi'sal margin of ba.sibrauchials, so that the 

 upper margin of the basibrauchials Ls liigher than that of the branchial arches. 

 In Scomher joponicu^s the fii-st basibranchial is nearly so short as the second, 

 and is bent a little downward. In Rastrdllger chrysozomts the fet basibranchial 

 is the longest, stiaight at the dorsal margin, whUe the second and third are 

 short and nearly equal in length. The third ossicle is bent downward at the 

 posterior half. In the Cybiidae the gi'ooves for the attachment of branchial 

 arches reach the dorsal margin of the basibranchials. Tlie anterior end of the 

 fhst basibranchial is more or less thickened. The second is bent downward 

 at the middle. In the Thuunidae the groove for the attachment of branchial 

 arches are very deep and reach the dorsal margin of the basibranchials. 

 The third Vasibrancliial is horizontally flattened. In the Katsiiwonida) the 

 basibranchials are laterally compressed and narrow. The anterior half of tlie 

 fii-st bii;Sibranchial ascends, and the tlurd is Ijent downward near the posterior 

 end. 



The branchial arches are armed with villous teeth, densely growing on 



