Paleontology. 



169 



structure to another in the phylogenetic history of 

 tails. This has been so clearly and so tersely conveyed 



Fiu. 67. Successive stages in the development of an existing Deer's 

 Antlers. (After Gaudry, but a better illustration has already been 

 given on p. 100.) 



A 



FIG. 68. Homocercal Tail, showing (A) external form and 

 (B) internal structure. 



by Prof. Le Conte, that I cannot do better than quote 

 his statement. 



