The Ephemerides, Osiander, Stark's Archives, Thiebault, van der Wiel, Chatton, and Schurig all speak of it, and it has been noticed since.

Danthez speaks of the development of a fetus in spite of the absence of an umbilical cord.

Stute reports an observation of total absence of the umbilical cord, with placental insertion near the cervix of the uterus.
There is mentioned a bifid funis.

The Ephemerides and van der Wiel speak of a duplex funis.

Nolde reports a cord 38 inches long; and Werner cites the instance of a funis 51 inches long.