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 ec’, 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. 
f'. The mcomplete 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. 
