220     MR.  R.  OWEN  ON  THE  HEART  IN  THE  PERENNIBRANCHIATE  BATRACHIA. 
the  left  auricle ,  and  by  the  orifice  e'  into  the  ventricle.  Bristles  are  also 
passed  through  the  inferior  cava  on  either  side  of  the  valvular  septum  c',  and 
one  of  them  by  the  orifice  of  the  right  auricle  d'  into  the  ventricle,  n  is  the 
coronary  vein. 
Fig.  3.  The  heart  of  the  Siren,  showing  the  structure  of  the  ventricle,  and  bulbus 
arteriosus, 
d',  e'.  The  auricular  orifices. 
/'.  The  incomplete  ventricular  septum, 
g'.  The  membranous  commencement  of  the  aorta, 
g".  The  valvular  projection  into  the  bulb. 
q.  Branches  sent  off  from  the  anterior  branchial  vessel  to  the  head. 
