Nuclear Phenomena in the Smuts. 
497 
imals today, and in which neither nuclear fusions nor loss of in¬ 
dividuality of the fusing gametes was present. Such cases 
would furnish an interesting connecting link between ordinary 
asexual reproduction by division and the sexual fusion of nuclei, 
with the resulting necessity of chromosome reduction and so 
forth. 
On the much discussed question as to whether the cytoplasm 
is concerned in the transmission of hereditary characters in 
true sexual fusions, such cases of cell fusions, showing that 
merely cytoplasmic unions have a distinct value for the organ - 
ism, make it probable that that advantage is a prominent feat¬ 
ure in the results of fusion of equal gametes in Spirogyra and 
other cases where large amounts of cytoplasm unite in the pro¬ 
cess of fertilization. In higher organisms, as already noted, 
where the amount of cytoplasm present in the male gamete has 
been reduced to a minimum, the significance of the non-nuclear 
elements in the fusing cells may be correspondingly diminished. 
Summarizing the types and apparent effects of cell fusions 
where no nuclear fusions occur, we can note the following:— 
1. Cases where fusion results in increased size thus enabling 
a germ tube to reach the substratum most favorable for its fur¬ 
ther development: Sclerotinia; possibly Nectria. 
2. Cases where fusion provides for more ready and equal dis¬ 
tribution of food materials in a mycelium: Rhyparobius and 
many others; also possibly the clamp fusions of Basidiomycetes. 
3. Cases where fusion leads to growth in size of the fused 
cells, perhaps also making them more resistant to unfavorable 
external conditions: Anther smut, Protomyces. 
4. Cases where the fusion is largely at least a nutritive 
phenomenon, the protoplasm of one energide passing entirely 
under the control of the other, and results in the disorganiza¬ 
tion of the nucleus of the former: Secondary fusions in the red 
algae according to Oltmanns. 
Madison , Wis., December , 1898. 
