254 SUMMARY OF THE WORKING HYPOTHESIS 



held as itself of primitive character. Whether the facts justify the con- 

 clusion that the megaphyllous types are derivations of a microphyllous 

 strobiloid ancestry, the fossil record does not disclose. The only avenue 

 to an opinion is then a detailed comparison of the known representatives. 

 It will be the object of the Second Part of this work to supply such 

 comparisons, relating not only to this important question, but also to the 

 whole theory of the strobilus, as stated in the First Part. 



