Dicephalic parapagus twins complete hearts are present as well, which improves their chances of survival. The total number of arms may be two, three or four. Their prospects are best if no attempt is made to separate them, except in cases where one twin is clearly dying. Dicephalus means two-headed. Parapagus means joined side by side. Dicephalic twins are called: Conjoined twins appear in one in 50,000 to one in 100,000 births. Dicephalic twins represent about 11 percent of all conjoined twins. As late as the 1960s, some medical publications argued that newborn dicephalic twins should not be actively treated or resuscitated. An
Tarzan and the Tarzan Twins it features Tarzan's first meeting with Doctor Karl von Harben, with whom he is already acquainted in "Empire". Because "Twins" is a children's book, however, it is customarily omitted from listings of the main Tarzan series. Thus "Tarzan, Lord of the Jungle" is generally considered the eleventh Tarzan book rather than "Twins". Two schoolboys, Dick and Doc, are cousins who resemble each other because their mothers are twins. As Dick is also related to Tarzan through his father, they become known as the Tarzan Twins. Invited to visit Tarzan's African estate, they become lost in the jungle and are imprisoned