Jan. 1904 ] Note on the Genus Harpochytrium . 
5 
which there was not room in the Plate illustrating my paper in 
the Annales (see text Fig. 33). 
Harpochytrium hedenii Wille. Figs. 24-26, on Vaucheria, Sweden; 27, 28, on 
Zygnema, Patagonia ; 29-32, on Zyguema, Tibet; 33, on Spirogyra, United States. 
These specimens from Dr. Lagerheim I think without doubt 
belong to H. hedenii. They were found growing on Vaucheria 
in an aquarium in the Botanical Institute of the Hogskolan, 
Stockholm. Several years earlier Dr. Lagerheim found what he 
thinks the same organism on Microspora stagnorum in Stads- 
hagen in Stockholm. He has searched again this last autumn 
for the same but the locality is so changed he was not able to 
find a trace of it. Dr. Thaxter of Harvard University informs 
me that he has found a species of Harpochytrium (which I sup¬ 
pose is H. hedenii) on Saprolegnia in Cambridge, Mass. 
With regard to the wide distribution of H. hedenii some 
would probably attribute the forms in such widely separated 
areas as Tibet, Patagonia, and the United States, as due to a 
polyphyletic origin. It seems more reasonable, however, to re¬ 
gard them as having a common origin. I have shown in my 
