Gill slits 



^Efferent 



Gill Arteries 



Pharynx 



Dorsal Aorta 

 Intestine 



Afferent Arteries ^Ventral Aorta 



Vascular System of Amphioxus 



Nerve cord 

 Notochord 

 Endostyle 

 Pharynx 

 Coelom 



Hepatic 

 caecum 



Hepati 

 caecum 



^Sub-intestinal 

 vein 



Gonad 



Hypobranchial 

 Typical Cross section Groove 



Nerve cord of 

 Amphioxus 



The Cardinal Veins 



Fig 3 Internal Anatomy of Amphioxus. The cross section shows the 



relative position of the structures. The top diagram gives the relationship 



between the digestive and vascular systems. 



