There is finally a condition in which union between the digits results in the disappearance of some of the fingers and toes (Fig. 98). This condition is called ectrodactylia. Supernumerary digits to the extent of six fingers and six toes are exceedingly common in the families of degenerates. The influence of heredity in this particular has been well demonstrated. The Kelleia family of Malta was one of the earliest reported. The condition may last for five generations,[224] but often disappears on marriage with normal persons outside the community or family. A family of the Arabian Hyabites, named Boldi, confined marriages to their own tribe. They all have twenty-four digits. Children born with a normal number are killed as being the offspring of adultery. The inhabitants of Cycaux, France, till the end of the eighteenth century, had nearly all supernumerary digits either on the hands or feet. Isolated in a mountainous region, they for years intermarried. On communication being opened, they emigrated or married strangers, and sexdigitism vanished. Maupertius reports the case of a German family whose members had twenty-four digits for many generations.[225] One of them refused to acknowledge a normal child. In one instance in the United States supernumerary digits lasted through five generations. A case reported[226] some years ago was the following: The first instance of the appearance of the deformity was in a man, born of a degenerate family in 1752, who had six toes on one foot. His son was born with six toes on one foot, but the daughter was normal. This daughter had five children; among them were a son and daughter, each of whom had six fingers on one hand. The granddaughter had eight children, including one son with six toes on one foot. Another son had two daughters, each having six fingers on each hand, and one daughter having twenty-four digits. This last girl had three children; the son was doubly deformed like his mother, while a second son had six fingers on each hand, the toes being normal. One of the two daughters of the fourth generation (with only the hands affected) had eight children, several of whom were normally developed, but the rest were deformed as follows: One daughter had an osseous thickening at the end of the digits, one son had twenty-four digits, another had twelve fingers, the toes being normal in number. [Illustration: FIG. 98.] [Illustration: FIG. 99.] I have elsewhere cited an instance from Kiernan in which unilateral sexdigitism was found in four generations of Norwegian degenerates.