142 
olivaceous, very slippery and of a rank odor—like some of the 
offensively strong-smelling marine alge. Flavor like kelp, but 
stronger and nauseating. 
Var. Ducluzelii, Ag. has been found only in the Giant 
Spring, near Great Falls. The first specimens were collected 
September 28, 1885, in avery rapid arm of the spring. They 
were plentifully attached to imbedded stones. The largest speci- 
men was three and a half inches high and none have been found 
so large since; the average height seems to be from an inch and 
a half to two inches; very dark green and olive-tinged, which 
shows more decidedly in dried specimens. This plant seems 
to appear only every other year; from August to October. 
In connection with this form attention is called to page 337 
of Wolle’s Fresh-Water Algz of the United States, whereon is 
mentioned a plant that might possibly be a form of Geltdium 
corneum, Lam. Only ascanty supply was collected, although it was 
fairly abundant at the time. This form has been carefully examined 
by Drs. Setchell and Farlow and by us, and the conclusion now 
is that it ismerely a condition of HV. fetidus var.. Ducluzeliz, in 
which the lateral branches, usually so liberally clothing the main 
stem, have not been developed. The microscopic structure of 
the two forms is practically the same. 
TETRASPORA GIGANTEA, Anders. and Kelsey, n. sp. Thallus 
attached to stones by the attenuate base, tubular or sometimes 
filled with an amorphous semi-fluid jelly which contains a few 
cells or none; cylindrical; end slightly tapering and rounded, or 
extended gradually into a long, slender, rounded point, one-eighth 
of an inch in diameter; one to ten feet long, diameter from a 
slender thread to an inch and a halfin the broad part, according 
to length and age of thallus: Cells 10-17, diameter, average 
size about 16m. Thallus bright green, becoming dilute green 
with age, smooth, very slippery, and easily ruptured. 
This species differs from Tetraspora cylindrica, Ag.:in its 
much greater size, in its remarkably conspicuous, gregarious 
habit, in the attenuate base and rounded apex and in the ten- 
dency to form cells throughout the diameter of the thallus as well 
as in having for a constant habitat the swift, turbulent mountain 
streams. The diameter of the cells is about the same in both, 
sometimes a little larger in ours, but the other features are so 
