84 Darwin, and after Darwin. 



these muscles persist, and are then described by 

 anatomists as abnormalities. The following illustra- 

 tions serve to show the muscles in question, when thus 

 found in adult man. 



FIG. 17. Front and back view of adult human sacrum, showing 

 abnormal persistence of vestigial tail-muscles. (The first drawing is 

 copied from Prof. Watson's paper in Journl. Anat. and Physiol., vol. 

 79 : the second is compiled from different specimens.) 



(6) Vermiform Appendix of the C&cum. This is of 

 large size and functional use in the process of digestion 

 among many herbivorous animals ; while in man it is 

 not only too small to serve any such purpose, but is 

 even a source of danger to life many persons dying 

 every year from inflammation set up by the lodge- 

 ment in this blind tube of fruit-stones, &c. 



In the orang it is longer than in man (Fig. 18), as 



