RISE OF COMPARATIVE ANATOMY 159 
the wing of a bat and the foreleg of a dog. Analogy is a 
superficial, and often a deceiving relationship; homology is 
a true genetic relationship. It is obvious that this distinction 
Fic. 44.—LaAcaze-DUTHIERS, 1821-1901. 
is of great importance in comparing the different parts of 
animals. He made a large number of independent discov- 
eries, and published a monumental work on the comparative 
