30 PEOCEEDINGS OF THE 



are, however, mauy other cases in which the simplificatiou of 

 particular organs means a real advance. 



A striking instance is the seed, an organ which required to be 

 much more elaborate in the days of spermatozoid-fertilization, 

 now only lingering in a few archaic survivals from the past (Cycads 

 and Ghikgo). The seed of an Angiosperm is, generally speaking, 

 a simple affair compared with that of a Pteridosperm or Cordaitean 

 of Palaeozoic age. We may add that the stamen of the higher 

 plants is extremely reduced as compared with the male sporophyll 

 of ancient forms such as the Mesozoic Bennettiteae. In such 

 cases (and innumerable other illustrations might be given, especially 

 from the flowers of advanced Angiosperms, where both andrcecium 

 and gyuceceum tend to a reduction) the reduction is correlated 

 with the more exact adaptation of a specialized floral mechanism. 



Taking into account all the causes whicli make for simplification 

 the question suggests itself whether, when we find a simple type 

 of structure existing at the present day, there is any presumption 

 in favour of its primitive nature. It has sometimes been urged 

 that such a presumption exists (except when direct evidence of 

 reduction can be adduced) on the ground that the general course 

 of evolution must have been from the simpler to the more complex, 

 a ru.le, as we have seen, subject to so many exceptions, that 

 within the limited period to which the palseontological record 

 extends, it has practically no validity. My own conviction is 

 that in such cases there is no j^resumption of primitiveness at all, 

 and that we should demand very strong evidence before admitting 

 that a given simple structure is primitive. Of course it may happen 

 that a primitive simple tj-pe, or at least an old simple type, may 

 have survived to our own day ; this may have been the case in 

 decaying families, where the less advanced members have had the 

 best chance of evading the competition of ascendant races. But, 

 on the whole, it is very unlikely that among all the changes and 

 chances of the world's history, a really primitive simplicity should 

 have been preserved. " The eternal ages are long " and there 

 has been time enough for many ups and downs on every line of 

 descent. 



The subject of reduction, so essential a clue in any attempt 

 to trace the course of evolution, suggests a reference to the 

 question of the simpler Angiospermous flowers. While the older 

 morphologists were wont to interpret such flowers {e. g. those of 

 Aroidese, Piperacese, Cupuliferae) as reductions from more perfect 

 types, there has been a tendency in more recent times to accept the 

 simpler flowers as primitive structures from which more elaborate 

 forms have been evolved. Quite lately, however, a reaction has 

 set in, due to the discovery by Dr. Wieland of the wonderful 

 bisexual flowers of the Mesozoic Cycadophyta, which are con- 

 structed on the same plan (though of course with many differences 

 in detail) as the more perfect Angiospermous flowers, such as 

 those of Magnoliaceae. The whole subject was put before the 



