MONOGRAPH OF THE LABOULBENIA.CEJS. 



229 



cell (/>) and an upper cell (z) ; while the cell (<?') has separated into a lower cell (//), 

 the secondary stalk-cell, and two upper cells only one of which is seen in the 

 figure, the second lying opposite it on the reverse side. The two cells (t f i) and 

 the cell (.: ) then continue to grow upward mound the base of the primordial cell of the 

 procarpc (r/), and the cell (g) becomes separated into a lower cell (fig. 17, o'), the pos- 

 terior basal cell, and an upper cell (n) ; while of the cells (i, i), one becomes separated 

 into a lower (o) and one upper cell («), the other into a lower (o) and tv/o upper cells 

 (n,n). The two cells (0,0) constitute the anterior basal cells, and thus, together with 

 the posterior basal cell (0), give rise to four cells (n,n), two only of which are seen 

 in the optical section (fig. 17). The cells (n, n) in the figure cited have already grown 

 up around the base of the primordial cell (d) of the procarpe, the base of which is 

 completely enclosed, and is separated from the free portion above as a distinct cell 

 (/), the carpogonium. In fig. 18, the cells (0,0') have also given rise to the inner 

 series of perithecial cells which develop as in Stigmatomyces, and are eventually all 

 destroyed. 



The free part above has in the mean time developed a terminal tricliogyne 

 (7 r), which is separated from the carpogonium by the trichophoric cell (e"). The 

 four cells (n. n) then continue to grow upward, and their upper portion becomes 

 separated by a septum. This upper portion then in turn divides into an upper and a 

 lower part, and the process is repeated several times, until the number of wall-cells 

 characteristic of the genus has been produced. During the formation of these wall- 

 cells a corresponding development of the inner series of perithecial cells, fig. 18 (not 

 shown in fig. 17), has taken place, resulting in the formation of the parietal and canal- 

 cells previously described, which correspond in number to that of the wall-cells, and, 

 like them, are derived as upgrowths from the three basal cells (0, 0, and o 1 ). 



The number of wall-cells which occur in a single row is usually four, as in 

 Laboulbenia and many other genera, while in Moschomyces, Compsomyces and a 

 few others, the number is five. As far as I am aware, the genus Ceratomyces (Plates 

 XXIV and XXV) is the only one in which the number may not only vary in differ- 

 ent species, but also in individuals of the same species. In this genus the perithecium 

 attains in some instances a most extraordinary development, and in C rostratus the 

 number of wall-cells in a single row may reach seventy. These rows of wall-cells 

 may be either straight, or spirally twisted, as in SHr/matomyces Bacri, or in some of the 

 species of Laboulbenia (Plate XIV, fig. 27; Plate XX, fig. 19), and vary in specific 

 cases both in form, relative size, and position. For example, in the genus Laboulbenia, 

 the lower members of the series of wall-cells, as a rule, lie opposite the ascogenic 



