Some aspects on the dermatoglyphics of normal and defective children in Bulgaria.

By comparison with a sample of normal Bulgarian children aged 3 to 18 years, children with visual, auditory and mental insufficiency differ in the relative frequency of pattern types on the digits. These differences are particularly noticeable on the second and fourth digits. It is suggested that the restriction to these two digits is related to the differing evolutionary histories of the different digits, and differences in their innervation.