Palceontology. 



169 



structure to another in the phylogenetic history of 

 tails. This has been so clearly and so tersely conveyed 



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

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

 given on p. 100.) 



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. 



