COMPARATIVE STUDY OF SCOMBROID FISHES. 
445 
know, pelagic and does not approach the coast. 
Kitahara (48) identified this species with Thymus sibi of Schlegel 
(67), but the latter author writes that the species is very 'common, during 
summer months, and is caught in hundreds at a time by means of nets of 
large dimension. This statement is not adequate for the present species. 
Moreover there are no decisive characters in the description by Schlegel, except 
the long pectorals and remarkable height of the body. Probably Schlegel con¬ 
founded this species with Neothunnus rnacropterus. Cunningham (10) considers 
this species to be identical with Thynnus obesus Lowe of the Atlantic ; but our 
species differs from the latter in the colour of the second dorsal, and the anal 
at least. According to Cunningham these fins have “ some black at edges, 
but little or no yellow.” The descriptions of Thynnus obesus by Lowe (52) 
as well as Cunningham are very incomplete. It is allied to the present 
species in having large eyes, and a short, thickset figure. But as the other 
important structures of Thynnus obesus Lowe are unknown, it is impossible to 
ascertain the relation between these two species. 
Recently the catch of this species is said to have much increased, due to 
the use of long snoods among snoods of normal length on a long line. The 
lower end of these long snoods will hang in a layer of water, deeper than 
57 m under the surface of the sea. At present this species is very common 
in the grounds near the mouth of Tokyo Bay. 
Genus Neothunnus gen. nov. 
Cutaneous blood-vessels are found from the segment of the seventh vertebra. 
Posterior cardinal vein is united to the right Cuvierian duct, and the former 
vein is connected with a plexus of blood-vessels in the haemal canal, so that 
the haemal arch is remarkably wide. The first haemal arch is found in the lltli 
vertebra. On the exterior surface of the liver we find no minute veins. 
Caudal vertebrae elongated, and accordingly the caudal portion long. 
Key to the the Japanese species of the genus Neothunnus. 
Air-bladder present, second dorsal and anal much elongated. N. rnacropterus. 
Air-bladder absent, second dorsal and anal slightly higher than the 
first dorsal. N. rams. 
