1028 ELLIOT ROWLAND DOWNING 
Dangeard thinks that reduction occurs during germination in 
Chlamydomonas. Prowazek’s work on Polytoma indicates that 
the same is true in this form. Illustrations might be multiplied. 
Hertwig, years ago, after careful study of many protozoa, con- 
cluded that either before, after or during the sexual union there is 
a reduction division. 
3. Among the protozoa and algae already cited, it is evident 
that reduction occurs when there is no alternation of generations. 
CHAMBERLAIN’S THEORY 
I have at some length presented what seems to me good evi- 
dence of the proposition that the alternation of generations and 
reduction are independent phenomena. JI have been anxious 
to make the matter emphatic, otherwise, in any comparison of the 
alternation of generations in the higher plants and animals, un- 
warranted conclusions are reached. Thus Chamberlain, in pro- 
posing a theory of the alternation of generations in animals says, 
The egg with the three polar bodies constitutes a generation compar- 
able with the female gametophyte in plants; similarly, the primary 
spermatocyte with the four spermatozoa constitute a generation com- 
parable with the male gametophyte in plants. All other cells of the 
animal constitute a generation comparable with the sporophyte gen- 
eration in plants, the fertilized egg being the first cell of this series. 
In support of this theorv I shall present two lines of evidence: (1) 
the gradual reduction of the gametophyte in plants, with the constantly 
diminishing interval between the reduction of the chromosomes and the 
process of fertilization; and (2) the phenomena of chromatin reduction 
in both animals and plants. 
Briefly, his argument is this: that since, in the higher plants 
the gametophyte is gradually reduced, producing a condition 
apparently identical with that in animals, the egg and its three 
polar bodies and the spermatids of animals are to be regarded 
as tetraspores and the gametophyte generation is undeveloped 
except as represented by these cells: that these cells are further 
proven tetraspores because, in their formation, reduction occurs 
in a manner very like the reduction in the formation of the tetra- 
spores of the higher plants. 
