126 EVOLUTION AND DISEASE. 
clear that if dichotomy lead to reduplication of the 
pelvis, four pelvic limbs should result. In typical 
specimens such is the case: two of the limbs being 
functional, and two usually occupying a median position 
on the ventral aspect, much smaller in size. 
Fic. 70.—Rana esculenta, with supernumerary hind limbs. 
A specimen of this nature was described in 1837 by 
Dr. J. van Deen. It occurred in a frog (Rana esculenta), 
(fig. 70), and was associated with a bifurcated condition 
of the termination of the alimentary canal. Van Deen 
gives a carefully detailed account of the dissection of 
this frog. It seems to be one of the earliest recorded 
