1 3 o E VOL UTION AND DISEASE. 



lived to twenty, thirty, or more years. Of the more 

 remarkable cases may be mentioned Jean B. dos Santos 

 of Portugal, and Blanche Dumas. The mode of origin 

 of paired pelvic limbs has been especially studied by 

 Professor Cleland. This anatomist has clearly demon- 

 strated that many of these are due to posterior 



FlG. 74. A Drake with a pair of supernumerary legs. 



dichotomy leading to reduplication of the pelvis. He 

 further points out that in living specimens of posterior 

 dichotomy, the functional limbs belong to opposite 

 pelves. In some it will be right limb of the right 

 pelvis and the left limb of the left pelvis. In such a 

 case the adjacent sides of the pelves and the associated 



