Note 226 — Chapter XXI
Reading edition
If Tonge is correct in his statement that the semilunar valves develop at some distance from the mouth of the ventricle, it would seem possible that the portion of the truncus between them and the ventricle ought to be regarded as the embryonic conus arteriosus, and that the distal row of valves of the conus (and not the proximal as suggested above, p. 639) has been preserved in the higher types.