474 THE AMERICAN NATURALIST. (VoL. XXXIX. 
zoölogical standpoint since it bears only indirectly upon the 
material of these papers. Zoölogists have, however, discussed 
critically Strasburger's suggestions (see Wilson, :00, p. 275, 
and Häcker, '98, p. 101). The difficulties of accepting this 
view of a possible antzthetic alternation of generations in animals 
seem insurmountable. In the first place there is not the 
slightest evidence of antithetic alternation of generations in the 
Metazoa or for that matter anywhere in the animal kingdom. 
The examples of alternation of generations which the zoölogists 
present among the Ceelenterates are all illustrations of omolo- 
gous generations derived from buds. There is no indication of 
spore formation comparable to the process in the higher plants, 
so far as I am able to judge, in any group of animals. And also 
there seems to be accumulating evidence of reduction phenomena 
previous to the development of sexual cells in the Protozoa 
which is essentially of the same character as in the Metazoa 
(see Wilson, : 00, pp. 227, 277, and Calkins, :o1, p. 233). It is 
very interesting and remarkable that reduction phenomena 
should show the same order of events in animals and plants and 
the facts should be clearly recognized. But I cannot follow 
those botanists who carry over to the animal kingdom the 
phylogenetic conclusions which are so clear in plants. The 
remarkable agreement of the events of sporogenesis in plants 
with gametogenesis in animals appears to me likely to prove 
only another illustration of similar biological phenomena which 
have evolved independently of one another, an illustration com- 
parable with the independent origin of sex, of heterospory, and 
probably even of the sporophyte generation itself (involving the 
processes of sporogenesis) in various groups of the plant king- 
dom. i 
We have considered this comparison of reduction phenomena 
in plants with animals chiefiy to emphasize the clear cut mor- 
phology of the process as understood by the botanist. It does 
not matter how close the events of sporogenesis may come to 
those of gametogenesis in the higher angiosperms, the whole 
background of plant phylogeny, which is wonderfully clear as a 
whole, shows that reduction phenomena are the product of the. 
asexual generation. It represents, as Strasburger has so well 
