758 Bachmann . — A New Type of Sperm ogonium and 
becomes attached to one of them. . In Rhynchophoromyces rostratus the 
small rod-like antherozoids bud distally and laterally from intercalary and 
undifferentiated cells of the appendages. In some species of Ceratomyces 
the single rods are replaced by slender long filaments which eventually 
break up into rods that probably function as antherozoids. Through the 
motion of the plant the trichogyne is brought into contact with the anthero- 
zoids, and Thaxter says it is probable that such antherozoids, in order to be 
functional, must become detached at the moment when they come in con- 
tact with the trichogyne. In the discussion above it was suggested that the 
greater activity of the trichogyne and the permanent attachment of the 
spermatia are a result of the land habit. Thaxter suggests that the adherence 
of the antherozoids to the mother-cell or to one another is an adaptation to 
ensure fertilization where the antherozoids might otherwise be lost because 
of the rapidly moving host. This seems entirely reasonable for the special 
case in question ; still, in general, it seems that the production of a large 
number of free male cells which are carried to the trichogyne in water 
is characteristic of the aquatic Algae, while the production of few and 
permanently attached male cells is equally a feature of the terrestrial Fungi. 
It may be that we have in the genera above mentioned land forms which 
have later become parasitic on aquatic insects, or it may be, as Thaxter (32) 
suggests, that we have here an adaptation to an isolated and rapidly moving 
host. 
In a following paper I will describe the development of the apothe- 
cium, together with certain nuclear phenomena. 
I am greatly indebted to Prof. R. A. Harper, at whose suggestion this 
work was begun, for helpful advice and criticism. 
Summary. 
1 . The spermatia of Collema pidposmn are not borne in spermogonia, 
but are few in number and are borne terminally and laterally on a hypha 
below the surface of the thallus. They are completely embedded in the 
thallus and are never set free. They are entirely homologous with the 
spermatia borne in spermogonia in other species. 
2 . The carpogones, as in other Lichens, are embedded in the thallus. 
These consist of a coiled basal portion, the ascogone, and a long terminal 
structure, the trichogyne. The trichogyne, the end cell of which is exceed- 
ingly long, does not grow towards the surface of the thallus and protrude 
from it, but instead grows more or less horizontally within the thallus 
towards the region where the spermatia are borne. The sexual apparatus is 
thus completely submerged in the tissues of the thallus. 
3 . There is a very evident attraction of the spermatia for the tricho- 
