430 KAMAKICHI-KISHINOUYE: 



towards the posterior end. The chiai portion is soft and poor in taste, and 

 contains about seven to fifteen times as much blood as the other portion, 

 estimating from the colour. 



Pylorus short, descending, runs along the inferior side of the stomach. 

 Duodenum receives at the posterior side five or six dendritic canals carry- 

 ing the tufts of pyloric coeca, and in bonitos two short tubes on the anterior 

 side as well. These dendritic tubes greatly vary in length. Each terminal 

 branch of these tubes ends with a tuft of coecal outgi'owths of nearly equal 

 size, and yellowish in colour. Each group of these tufts is covered with a 

 membrane, and the whole mass of these tubes is covered with a thick 

 membrane to form a compact mass. In these tuljes we find a half digested 

 mass of food, but in the yellow tufts we have not found it yet. 



Myotomes at the surface of tha body are bent with acute angles at 5 points, 

 so that we find more than ten concentric circles in the cross-section of the lateral 

 muscle in each quadi'ant. There are three myotomes in the cepliaUc region, 

 and generally we find an auxiliary intermusclar bone between the Lost two. 

 Myotomes in the caudal pedimcle seem to have been reduced in number. 

 Moreover the terminal tendon of these myotomes are well developed, and may 

 be distinctly seen at the outer surface of the muscle, when we remove the skin. 



The vascidar system is very complicated and variable in different membei*3 

 of the group. Besides the cutaneous vascular system ^re find many peculiari- 

 ties. It is remarkable that ia the ancestral forms of tmmies the posttn-i(ir 

 cardhial vein does not poiu- dh-ectly into Cuvier's duct. In these timnies 

 the principal veins uniting with the Cuvierian ducts are two large cutaneous 

 veins carrying blood from the dark r>?d portion of the lateral muscle, and the 

 anterior jugular veins. The posterior cardinal vein is insignificant and communi- 

 cates mtli Lateral commissures at tlie caudal peduncle to the cutaneous veins 

 mentioned alxive. In these forms hepatic portal veins form a massive plexus 

 OQ the axial side of each lobs of the liver. In more advanced forms, 

 however, the posterior cardinal veiu is well developed and imited with the 

 right Cuvierian duct. In these forms the venules flowing downwards fi"om the 

 dark red portions collect to the comparatively spacious haemal canal, and 

 there they are divided into many short parallel transverse canals, wlut-li fill 

 up the canal entirely, forming a solid mass in it. In still naore mollified 



