450 KAMAKICm KISHTNOUYE : 



in association with small bonitos. 



This species feeds, S3 fai" as I know, on small fishes only; — one specimen 

 contained two mackerels in its stomach, the second specimen fom*teen examples 

 of Stdlepliorus glacilis, and the third three half-beaks and some anchovies. 



On December 17th, 1918, one of this species was found dead on the 

 beach near the mouth of Gönokawa, the largest river in Shimane-ken, 

 probably scared by killer- whales or some other ferocious enemies. 



Famüy KATSÜWONIDAE Kishinouye. 

 KatsuwopMae, Kishinouye, 1917. 



Body plump, rounded in cross-section, and naked outside of the coi'selet. 

 Lateral line without a marked undulation above the pectoral fin. Firet 

 doi-sal very high at the anterior end, becoming suddenly low behind. Second 

 dorsal remarkably lower than the first dorsal, and the anal and second doi-sal 

 are smaller than the ventrals. Pectorals very short and triangular. In this 

 family the haemal canal is closed behind the middle of the precaudal region. 

 Dentition weak, generally only one row of small teeth in both jaws. When 

 teeth are found in other bones, they are arranged in one row only, never 

 more. On the roof of the mouth-cavity no dentigerous calcareous plates. 

 Tongue smooth with a ridge on each lateral side. No air-bladder. Pyl inc 

 coeca minute, numei'ous, uniform in size, and developed on the terminal branches 

 of pyloric tubes, an-angea on both sides of the duodenum. The loose and 

 thick membrane sun'ounding the stomach in the Thunnidae is not found in this 

 family. Three lobes of the liver imequal, and generally the right lobe is much 

 elongated, except in the genus Katsuivonus. Intestine very short, without a loop. 

 Kectum is nearly the same in length or a little longer than the remaining part 

 of the intestine. The longitudinal folds of the internal layer of the duodenum 

 extend to the straight small intestine, just to the beginning of the rectum. 



The circulatory system which is related to the formation of the dark red 

 portion of the lateral muscle, differ more or less fi'om that of the Thunnidae. 

 In the present family the cutaneous blood-vessels are also two in number, on each 

 side of the lateral median line ; but the hypaxial vein is divided to renal portitls, 

 and the hypaxial artery passes through the kidnej-s, taking a slight downward 

 coui-sc, and runs backward anterior to and above the series of the ribs. Except 



