62 



ZOOTOMV. 





ek./ 





FIG. 20. Raja nasuta. The arterial system, seen from the ventral 

 aspect (one-third nat. size). 



The heart and ventral ao^a (v.ao) are slightly displaced towards the 

 right side (left in the figure) : the left afferent branchial arteries (a.h) 

 are removed, and the right efferent branchials (e.br) : the lett efferent 

 branchials are straightened out, so as to bring their ventral ends to the 



