EXTRA DIGITS AND DIGITAL REDUCTIONS 341 



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 An rutins, as may be seen by comparing A and B 



Fig. .">. 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 pha- 

 langes, was produced, and these in turn exhibited all stages of duplica- 

 tion up to the formation of two large extra toes. But in each case 



