FaulL—The Cytology of the Laboulbeniales. 653 
lower ones on the spindles of the last mitosis. There are some reasons for 
believing that the same is true of Amorphomyces and Dioichomyces , in which 
case sexual differentiation of the spores might be determined in the second 
division. 
Relation to Host, and other Factors. 
The foot of such forms as Laboulbenia Gyrinidarum and L. chaetophora 
lies closely appressed on the surface of the host, but does not penetrate its 
chitinous covering or produce any visible changes in its underlying tissues. 
This is not true of all, however, as, for example, of Stigmatomyces , Dirnero - 
myces , and Dioichomyces. In the last there is a distinct hypertrophy of the 
tissues in the neighbourhood of the point of attachment of the fungus, 
and in the two former there is, especially under the older and larger tufts, 
often a disorganization of a more or less extensive patch of cells, which 
sometimes extends through the entire body wall. I have not had the 
opportunity of examining any species possessing rhizoids. 
Whatever part the appendages play in the life of the fungus, that is 
to say, as to whether or not they act to a certain extent as absorbing 
organs, it may be stated here that their cells are well nourished throughout, 
exhibit some power of regeneration, and do not show signs of senescence 
often seen in the larger cells of the receptacle. 
The members of several species—for example, of Stigmatomyces and 
Dioichomyces —lie flat against the hosts in their earlier stages of develop¬ 
ment. At maturity, however, the stalk cell of the receptacle bends so as 
to bring the plant into a position approximately at right angles to its 
former one. The young plants thus appear to enjoy the advantages of 
greater security against desiccation, and in the later stage spore dissemina¬ 
tion is facilitated. 
The moisture relation also exhibits itself in the relative thickness and 
permeability of the chitinous general envelope. In Zodiomyces and other 
aquatics this membrane is usually much thinner and more permeable than 
in terrestrial forms. The same may be said of species that grow on the 
under side of the body in comparison with those that grow in more exposed 
situations. This fact may be readily confirmed by reference to species of 
Dioichomyces , two or three of which are often to be found on the same 
insect, or to individuals of a species not restricted to a limited position on 
the host. 
Theoretical. 
One of the most obvious conclusions to be drawn from a cytological 
study of the Laboulbeniales is the fact of their evident Ascomycetous 
nature. The spore sac has quite the same right to be designated an asciis 
as has the spore sac of the most typical Ascomycetes. As to their place 
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