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
Kalin Twins Kalin Twins The Kalin Twins (born February 16, 1934) were a pop music recording and songwriting duo, comprising twin brothers Harold Kalin and Herbert Kalin (died August 24, 2005 and July 21, 2006, respectively). The Kalin Twins, who were known affectionately as "Hal and Herbie", are best known for their 1958 hit "When". The twins were born in Port Jervis, New York. Originally discovered by Clint Ballard, Jr., the writer of many hit records such as "Good Timin'" for Jimmy Jones, and "I'm Alive" for The Hollies, the sibling duo had a couple of early recording flops. However, in 1958,