Laboulbcnia chaetophora and L. Gyrinidarum . 329 
general envelope and often bears no apparent relationship to the protoplasts 
(Fig. 9). At a comparatively early stage the differentiation in structure 
referred to above becomes evident. At first it is little more than a mottling. 
The changes in structure, however, vary in different parts of the plant. In 
some regions there is a more or less uniform granulation of the lamella, in 
others the appearance of a radially arranged system of deeply stained rays 
grouped in plates. Reference to Figs. 9 and 14 will make clear what is 
meant. Viewed in section these plates look like dark, compactly striated 
bars of varying width, while viewed from the surface they resemble a honey- 
comb or net. With increasing age the plates disintegrate into granules, 
until finally the lighter areas, the meshes of the net, composed of the 
apparently almost unmodified wall substance, stand out as anticlinally 
oriented strands. In these changes it sometimes happens that one or more 
of the subjoined layers may become involved, but only secondarily so. 
The strands which originate in this curious way are of very common 
occurrence in species of the genus Labcndbenia , and are of very characteristic 
appearance. Figs. 10 and 12 represent the fully formed strands. By light 
reflected from their surfaces they appear quite black in stained preparations, 
but by transmitted light are light-coloured and bright, the latter quality 
being due to their comparatively high index of refraction. Fig. 11 re- 
presents a portion of the general envelope that has been pulled away by 
the knife, and to which several of them are attached. The surface of such 
a portion of the plant viewed by transmitted light appears pitted or porous 
(Fig. 12). Indeed, Istvanffi (’ 95 ) described this punctate appearance, but 
interpreted the punctations as 4 pore canals ’. Thaxter rightly associated 
them with these strands or fibrillae, to the existence of which he was the 
first to call attention. Their formation, as has been seen above, is due to 
a more or less complete disintegration of the outer laminae, and in particular 
of the outermost. But as to the cause of this one can only conjecture. 
Instead of a granulation or degeneration of portions of the substance of the 
wall, as just described, in some instances there may be nothing more than 
a shredding, which is either an artifact or due to an unwonted stretching of 
an inelastic membrane. But shredding is exceptional, and cannot be offered 
as the cause of the origin of the ordinary type of fibril or the curious 
differentiation of the wall so early expressed in the life of the plant. 
This account of the general envelope and external cell- walls does not 
apply to those of the trichogyne, the appendages, and the inner cells of the 
perithecium, all of which remain comparatively thin. Because of this fact 
the fixation of the appendages is usually good. In passing it may be 
pointed out that the appendages, in this species at least, appear to be 
capable of regeneration to a marked degree. New branches frequently 
spring from injured ones to replace the portions that may have been de- 
stroyed. The terminal cells in particular are long and thin walled, and are 
