there can be seen a paie yellow nimbus. The ova are perfect 

 spheres J, no structures being visible on the vitelline membraneo 

 The figure differs depending on the size of the fishp but in 

 an individual of 270 - 300 kgo the number of ova ripened at 

 one time is IpOOOpOOOo 



Nothing at all is known as yet of the form of the larvae 

 just after hatching^ nor of the course of development that they 

 followo In late summer fish of about 250 nrnio body length and 

 20 gro weight can be taken on pole and lineo Such fish are 

 called imoshibi in Miyazaki Prefecturep kakinotane in Kanagawa^ 

 and abuko or bintsu in the Mie Prefecture areao On fish of 

 this size 10 - 15 pale stripes can be seen on the sides^^ 

 These transverse bars are divided into two on the belly j, and 

 they gradually fade out as they approach the midline of the 

 bellyo By winter they are already about 400 mmo in lengthy 

 by the following spring they are 600 mm„ j, and by summer they 

 have grown to about 2-3 kg. In Formosa around February fish 

 about 400 mmo in length are taken only very rarely, and the 

 larval stages are almost never seen„ At this stage they often 

 form schools together with frigate mackerels and their food 

 is mainly planktonic crustaceanSo 



As noted above,, the growth of the black tuna is extra- 

 ordinarily rapido 



No concrete data have as yet been obtained concerning 

 the spawning habits of the albacorep the big-eyed tuna, and 

 No raniSo 



For the yellowfin too^, no exact information has been 

 obtained other than the hypothesis that they probably spawn 

 in the warm seas of the southc In recent years in Formosa 

 the author has collected a large number of eggs from ripe 

 ovarieso The season has been around March = Mayo The yellow= 

 fin taken in the South China Sea at about that time generally 

 have well ripened gonads, and from this circumstance it is 

 thought that in these waters the spawning season of the 

 yellowfin is around March ■= Mayo In the series of enclosed 

 seas composed of the Celebes Sea, the Banda Sea, and the 

 Flores Sea, it appears that spawning" also occurs, with the 

 seasons apparently overlapping som.ewhato 



The form of the eggs is absolutely the same as that of 

 the eggs of the black tuna, and it is difficult to distinguish 

 them by their outer appearanceo 



From April to June the so-called kimejl /small yellowfiriT" 

 appear in large numbers off the east coast of Formosa where they 

 are taken in trap netso They are about 500 mmo longo Such 

 fish are also taken in the Okinawa area about the same time„ 



15 



