Image: Homologous Stuctures in Tetrapod Limbs

Homologous structures in the tetrapod limb, modified for various functions. Notice that the various bones, which are tinted different colors, have been modified in different ways to accomplish each type of locomotion (e.g., compare the modifications of the bones for flight). From Audesirk/Audesirk, BIOLOGY: Life On Earth, 5/e, © 1999. Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey. Figure 14-8.