166 ( ts ) 



specting lapse of time is an unwarranted assumption 

 that some are forward to make. If it changes the views 

 of some respecting the parallelism or coexistence of 

 faunae in different regions of the earth, it is only the 

 nnti-developmentalists whose position must be changed. 

 For, if We find distinct geologic faunae, or epochs de- 

 fined by faunae, coexisting during the present period, and 

 fading or emerging into one another as they do at their 

 geographical boundaries, it is proof positive that the 

 geologic epochs and periods of past ages had in like 

 manner no trenchant boundaries, but also passed the 

 one into the other. The assumption that the apparent 

 interruptions are the result of transfer of life rather than 

 destruction, or of want of opportunities of preservation, 

 is no doubt the true one. 



& Rationale of Development. 



a. In Characters of Higher Groups. It is evident in 

 the case of the species in which there is an irregularity 

 in the time of completion of metamorphosis that some 

 individuals traverse a longer developmental line than 

 those who remain more or less incomplete. As both 

 accomplish growth in the same length of time, it is ob- 

 vious that it proceeds with greater rapidity in one sense 

 in that which accomplishes most : its growth is said to 

 be accelerated. This phenomenon is especially com- 

 mon among insects, where the females of perfect males 

 are sometimes larvae or nearly so, or pupae, or lack 

 wings or some character of final development. Quite 

 as frequently, some males assume characters in advance 

 of others, sometimes in connection with a peculiar geo- 

 graphical range. 



