650 Fault.—The Cytology of the Laboulbeniales. 
phenomenon has been noted frequently in Ceratomyces and Laboulbenia. 
The same thing is true of the nuclei of the richly stored inner cells of 
the perithecium. 
The nucleus divides mitotically, not only in the young spores and 
thalli, but also in the older cells. An ordinary spindle is formed at each 
division, on which are arranged the chromosomes, and at each end of the 
spindle there is a central body. 
The entire plant body is enclosed by a thin chitinous membrane that 
is exceedingly resistant to the penetration of fixing reagents. The walls of 
the cells are thick and laminated. Those that separate cells of common 
origin contain a single deep pit, interrupted only by the middle lamella. 
There are protoplasmic bridges, but sometimes, as in the receptacle and 
perithecium of Laboulbenia chaetophora , they are very tenuous. 
The cytoplasm is finely granular or spongy-reticulate, and often con¬ 
tains abundant granular inclusions, or globules of oil. Very often, especially 
in Laboulbenia , one finds a more or less clearly defined organization of 
cytoplasmic strands bearing a definite relation to the pits or to the nuclei. 
The Antheridia. 
The antheridia, as is well known, are of two general types— exogenous , 
as in Zodiomyces , and endogenous, as in Laboulbenia. The endogenous are 
again of two sub-types—simple, as in Stigmatomyces , and compound, as in 
Dichomyces. The antheridia are usually borne along with the female organs 
on the same plant, but in Amorphoniyces and a few others the sexes are 
separate. 
Exogenous antheridia were studied in Rhyncophoromyces and Zodio¬ 
myces. They were found to be uninucleate. The spermatia are formed as 
short lateral branches at the upper end of the antheridia, and they, too, are 
uninucleate. There are indications, in my preparations of Rhyncophoro¬ 
myces , that the spermatial rods, as soon as they drop off, are replaced by 
the outgrowth of others from the same base, in which case the antheridial 
nucleus must undergo repeated divisions in order to supply each spermatium 
in turn. 
Simple endogenous antheridia were studied in Stigmatomyces , Dioicho- 
myces , Amorphomyces , and Laboulbenia. The antheridium is invariably 
occupied by a single nucleus. Prior to the formation of a spermatium the 
nucleus divides mitotically, and the chromatin destined for the upper 
daughter nucleus, the nucleus of the male element, is literally pushed during 
the telophase stage of division up to the mouth of the efferent tube by the 
remarkably orientated and elongated spindle fibres. This phenomenon is 
regularly repeated at the birth of each spermatium. The spermatia contain 
a relatively large nucleus and a small amount of cytoplasm, and appear to 
be covered by nothing more than a thin protoplasmic membrane. 
