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. 
