Bordenave is quoted as mentioning a human monster formed of three fetuses, but his description proves clearly that it was only the union of two.

Probably the best example of this anomaly that we have was described by Galvagni at Cattania in 1834.
This monster had two necks, on one of which was a single head normal in dimensions.

On the other neck were two heads, as seen in the accompanying illustration.

Geoffroy-Saint-Hilaire mentions several cases, and Martin de Pedro publishes a description of a case in Madrid in 1879.

There are also on record some cases of triple monster by inclusion which will be spoken of later.