MIGBATOBT FISHES OF ASIA. 207 



and after traversing their corresponding branchial arch, they take 

 their way to the dorsal respiratory air-sacs (h), on the surface of 

 which numerous lateral branches spring from the principal longi- 

 tudinal vessel. This vessel at the respiratory sac is along the 



A dissection showing the air-sacs and circulatory apparatus in Saceobranchus, 

 altered after Hyrtl. 

 a «, air-bladder ; 6 b, respiratory air-sacs ; c, bulbus arteriosus ; d, vessel of 

 right side, from anterior branchial pair ; e, vessel of left side, from fourth bran- 

 chial pair ; /, vena arteriosa, communicating with branchial vein of fourth pair 

 of branchiae. 



dorsal surface (d) of the right side, and on the ventral surface (e) 

 of the left ; and each of them gives oif a branch to the posterior 

 wall of the branchial cavity, the mucous surface of which is pro- 

 vided with a network of respiratory capillaries. 



The blood having passed through the capillaries of the respira- 

 tory air-sac, is collected into a vena arteriosa (f), which commu- 

 nicates with the branchial vein of the fourth pair of branchiae, and 

 the blood is driven, together with that returning from the other 

 branchiae, to the common aorta. 



Some independent branches, going to muscles of the back &c., 

 spring from the vena arteriosa of the respiratory air-sac even before 

 its contents have entered into the general circulation by the more 



