376 SCIENCE PROGRESS. 



when they do not acquire substantial support from com- 

 parison of less variable parts, such as the archspouia. We 

 shall be disposed therefore to agree with Professor Campbell 

 in his main point. But it must not be thought that the 

 priority of Eusporangiate forms is proved; few cases are 

 proved or susceptible of proof in morphological discussion. 

 The most that can be done is to show a preponderance of 

 probability, and this we believe has been done in the present 

 case. 



F. O. Bower. 



