Craniopagus twins conjoined twins develop inutero remains unclear. Embryologists have traditionally attributed identical twinning as "splitting or fission" of either the inner cell mass of pleuripotential cells or early embryonic disc at 13–14 days of gestation just before the primitive streak. Some theorists suggested that conjoined twins develop as a result of the failed fusion of a single fertilized ovum. However a new hypothesis suggests that cranial fusion occurs between two separate embryos before the end of the 4th week of gestation. This can happen because the cranial neuropore is still open, which is responsible for the ultimate fusion and formation of
Otherwise Known as Sheila the Great Tubman- Sheila's thirteen year old sister, who's a ballerina and is boy crazy Merle "Mouse" Ellis- Sheila's friend in Tarrytown, who is the junior champion of yo-yoing. She's a champion swimmer, and a dog lover Betsy Ellis- Mouse's four year old sister, who's also a champion swimmer. Since she's allergic to dogs, she has a make-believe dog called Ootch Sondra and Jane Van Arden- The Van Arden twins, who are good friends with Sheila and Mouse. They both are very excellent swimmers and both get easily offended. They all argue at a sleepover. Marty- Sheila's swimming teacher, who struggles to