Laboulbenia chaetophora and L . Gyrinidarum . 331 
investigations on a large range of forms. The extent of his observations 
may be judged from the fact that he drew his material from the following 
groups : Mucorini, Ustilagineae, Uredineae, Agaricineae, Polyporeae, 
Hynaceae, Tremeliineae, Clavariaceae, Hymenogastreae, Lycoperdaceae, 1 
Nidularieae, Saccharomycetes, Perisporiaceae, Hypocreaceae, Pezizeae, 
Helvellaceae, Tuberaceae, Parmeliaceae, and Cladoniaceae. In every in- 
stance -Wahrlich found that the transverse septa were perforated by a single 
simple pore. In only one species, however, did he find protoplasmic bridges 
that closely resembled those of the Florideae, and of the Dactylium recorded 
by de Bary. 
A. Meyer (’ 96 ) has also examined the Fungi from this standpoint quite 
independently of Wahrlich’s publication, and later (’0.2) published an ex- 
tended account of his researches on protoplasmic bridges and cell fusions in 
the Fungi, in which he fully corroborates the observations of Wahrlich. 
Baur (’ 98 ), Darbishire (’ 99 ), Woronin (’00), Strasburger (’ 01 ), and Kienitz- 
Gerloff (’ 02 ), and others have made more or less extensive examinations of 
the protoplasmic bridges in various Fungi and lichens, and all noted their 
existence. 
It is aside from the purpose of this paper, however, to review the 
literature on this subject, except in so far as it touches the Laboulbeniaceae, 
the only account of which is given by Thaxter (’ 96 ). Concerning proto- 
plasmic bridges in the Laboulbeniaceae, Thaxter offers the following : 
‘ The protoplasm of adjacent cells, the origin of which is the same, is 
connected by a strand of the same substance, which passes from one cell to 
the other through a well-marked perforation of the cell-wall, the connexion 
being demonstrated with great ease by treatment with potash and sub- 
sequent staining (PI. Ill, Figs. 11-12 ; PI. II, Figs. 16-18). In many 
instances, also, it may be seen in the living plant without the use of reagents. 
This protoplasmic connexion is found in all the cells, including those of the 
trichogyne, when this organ is multicellular. In many cases in which the 
cells had been separated by potash, and the connecting protoplasmic strand 
stretched between them, I have seen a slight enlargement like that indicated 
in Fig. 12, PL III, recalling the similar structure through which the strands 
of protoplasm pass in the Florideae. I have, however, been as yet unable 
to determine its exact nature.’ 
Judging from microtome sections of the forms described in this paper, 
the thickening to which he refers may be the middle lamella, together with 
the granular accumulations to be found on both sides of it. The rather 
violent treatment of gross material with potash, followed by maceration, 
might very well tear out a portion of the middle lamella along with the 
strands. In this connexion Kienitz-Gerloff’s (’ 02 ) ‘ Neue Studien iiber 
Plasmodesmen ’ are of interest, as they deal with the bridges of the Florideae. 
He was able to verify the observations of Wahrlich and Meyer on 
