MONOGRAPII OF THE LABOULBENIACEyE. 



235 



nected with the outer layers of the cell walls, and, though always readily demonstrated 

 by crushing, is not affected by the application of potash. 



The cells of the Laboulbeniacece, with the exception of those which lie within the 

 wall-cells of the perithecium, and of the receptive portions of the trichogyne, are char- 

 acterized by possessing thick walls that, when treated with potash, are readily seen 

 to consist of a number of layers, the outer of which are less dense, and soon become 

 swollen and gelatinous. In a majority of instances they do not seem to be connected 

 with the general surrounding envelope by any special organs of attachment ; but, in 

 certain cases, the innermost layers of the cell wall give rise to fibrillaa which, passing 

 through the outer layers, are attached to the inner surface of the envelope. The 

 latter, in such instances, is usually more or less conspicuously punctate, especially in 

 cases in which it is suffused with some dark color, as, for example, in the sub-basal 

 cell of Laboulbeiiia ObeHhuri (Plate XXII, fig. 39). It may be mentioned in passing 

 that the suffusions, usually of black or brown, which characterize many of the species, 

 appear to be for the most part, if not entirely, confined to the envelope ; the cell walls 

 within them being, in general, hyaline. 



In some cases, however, this blackening involves at least the outer layers of the 

 walls themselves, as, for example, in the ordinary " foot." The same is true also in 

 cases where, for instance, the septum separating two cells is thus modified. This 

 occurs very frequently in the appendages of Laboulbenia and other genera, the black- 

 ening extending inward so that it appears to form a disc with a central perforation 

 corresponding to the passage through which the protoplasm of adjacent cells is con- 

 tinuous. These blackened septa were noticed by Berlese, and described in his 

 account of Laboulbenia armillaris as " black discs or rings," the nature of which was not 

 determined. 



The fibrillae just mentioned, which, in the normal cell wall when it is viewed in 

 optical section, give rise to the appearance described by Istvanffi as being due to the 

 presence of " pore-canals," are more or less twisted when freed by treatment with 

 potash, and are characterized by the presence here and there of granular thickenings 

 (Plate III, figs. 11 and 12), their extremities being attached to the inner surface of 

 the general envelope in a fashion that varies in different instances. In Laboulbenia 

 Kunkeli, for example (Plate XVIII, fig. 9), they are characteristically attached in short 

 rows, running transversely in the sub-basal cell, but less regularly disposed in the cells 

 above it. In other cases they may adhere in more compact groups, as in L. Ncbriw, 

 or singly without any definite and characteristic aggregation. These points of 

 attachment tend to become dark-colored, especially in areas where the envelope itself 



