coMr.vnixn'E study of scombroid fisqes. 



349 



be the mcKliiui sn^xn-ficLil part, while iu the Plocostei it seems to be the deeply 

 seated "cliiai" pirtinn. In the Teloostei the dark coloured portion gfr'w^un.Uy 

 btioomes broader and tliicker in the caudal portion, passing beyond the hmit 

 of the median snperficijü lateral mascle. I have examined and foiuid that the 

 dark red portion contains alx)iit 7 times as much blood as the other portion 

 in Tinmnns oricrUalis, and about 15 times as much as in Parathunnvs mehaclti. 

 In Scomber japonicvs the superficisd red muscle contains almost 8 times a? 

 much blixxl as the other flesh, and in Cijhium niphonium the superficial red 

 muscle contains 12-13 times as much blood as the ordhmi-y flesh, which is 

 nearly colourless. 



Histolc^cally the dark red portion consists of uniform and fine fescicles, 

 with many capillaries among them, and theii' mucle-fibres ai'e faintly striate«!, 

 more or less resembling the involuntary muscltvfibres. AVhen the dried muscle 

 of tunnies or bonitos are broken h'ausversely, tlie chiai portion is rather rough 

 and not lustrous, while the other portion is quite smooth and conchoidal. 



In the Katsuwonidae the chiai portion is better developed than in the 

 TliTumidiie, and both the epaxial and hypaxial pai'ts of it reach the vertebral 

 column, as the chiai portion 1ms a wider base than in the tunnies, and as 

 the segmental blood-vessels nom-ishing the portion originate on each side of the 

 dorsal aorta and its plexus at 

 two points, a httle above and 

 more or less below the verte- 

 bral column. 



To the ventral side of the 

 vertebral column a pair of 

 cylindi'ical muscles ai'e insert- 

 ed to suspend the pLarynx. 

 These muscles run obliquely 

 forwards fi'om the veiiebral 

 column. These pharyngeal 

 muscles are inserted into the 3rd 

 and 4th vertebrae in Scomha' 

 Japonicvs, to tlie 4th in Bastrd- 



Dark red portion I'twi-uiac jikxus 



Fig. J. Cross section of the lateral muscle, show- 

 ing the large fassicles of the ordinary portion on the 

 right side, anj fine dark coloured fascicles of the dark 



liger chryaozomis, to the 3rd re»i portion on the left. 



