spiral valve of conus arteriosus
The spiral valve alternately blocks & unblocks the entrances to the left and right pulmonary arches (sending unoxygenated blood to the skin & lungs). [ http://people.eku.edu/ritchisong/342notes9.html ]
Term info
spiral valve of conus arteriosus
uberon
UBERON:0010018
found in dipnoans and amphibians, The spiral valve is considered to have evolved from the right member of the four embryonic endocardial ridges (Goodrich, 1930 - via Morris 1974)