Order Plecostei should naturally be discarded <> In short , the Order 

 Plecosteij, which is established solely on the basis of a partial varia- 

 tion in the highly variable vascular system, and actually only in the 

 minor details of that system^, cannot exist in an equal status with the 

 other four Orders of the Xeleostomi and should therefore be thrown out» 



In conclusion I wish to express my heartfelt thanks to my teacher, 

 Professor Chiyomatsu Ishikawa, for his constant encouragement and for his 

 valuable advice in the gathering of my material and the writing of this 



papero 



^Explanation of -Figures 



Figure 1 koshinagashibi ( Neothunnus rarus Kishinouye) 



Part of the subcutaneous vein and part of the muscle tissue anterior 

 to the sixth myotome have been cut away, and the smallT»ss els originating 

 from the subcutaneous vessels have been omitted o 



Figure 2 marumejika (Auxis naru Kishinouye) ground frigate mackerel/' 



Vessels originating from the subcutaneous vessels have been omittedo 



Figure 3 mekajiki ( Xiphias gladius L D ) £broadbill swordfis^y 7 



Parts of the opercle and the pectoral girdle have been cut away, and 

 the small vessels originating from the subcutaneous vessels have been 

 omittedo 



Figure 4 bashokajiki (Is tiophorus orientalis r o et S„) ^jsailfish^ 



The ventral portion of the lateral muscle tissue has been cut away» 



Figure 5 saba ( scomber japonicus houttuyn.) ^/mackereiy' 



The third myotome has been cut away and the small vessels originating 

 from the segmental vessels have been omitted* 



Figure 6 aomishimaokoze ( Gnathagnus alongatus T et S D ) 



All of the pectoral girdlj and a part of the opercle have been cut 

 away* 



Figure 7 shiira y ioryphaona hippurus L ) ^dolphin/ 



Part of the pectoral girdle has been cut away 



Explanation of Abbreviations Used in the Figures 



a dorsla aorta ca subcutaneous artery 



cv subcutaneous vein d dark lateral tissue 



ecv epaxial subcutaneous vein hca hypaxial subcutaneous artery 



15 



