Page:Popular Science Monthly Volume 68.djvu/345

Rh distal end of the metacarpal bone were developed (Fig. 4, B) and in several cases a perfectly formed pollex was present (Fig. 4, C). In its general structure the manus of such polydactyl pigs resembles closely that of the fossil swine Ancodus, as may be seen by comparing A and B

 A series of four X-ray photographs showing variations and duplications of the pollex (I.) in the manus of the pig. A, a manus in which the pollex is represented by an abnormally large digit of three phalanges; B, the phalanges of the extra digit are duplicated: C, all the bones of the extra digit are duplicated, but both sets of phalanges are enclosed within a single hoof; D, two extra digits are present, articulating with a single trapezium (trz.).

of Fig. 3. In other instances not a pollex, but a digit of three phalanges, was produced, and these in turn exhibited all stages of duplication up to the formation of two large extra toes. But in each case