224 



MONOGRAPH OF THE LABOULBENIACE.E. 



further upward, destroys the two remaining series of canal-cells (cc and t c), and 

 finally forcing their way between the lip-cells (w z) the spores make their exit 

 through the permanent pore thus formed. 



The special instance which has been selected as an illustration of the development 

 of the female organ, although it may be considered typical of the process as it occurs 

 in the family generally, does not, as has been noted, represent the invariable course of 

 development in all cases, when the details of the successive changes are considered ; 

 and it will therefore be necessary to compare the processes described with the corre- 

 sponding conditions presented by certain other genera. 



The exact point of origin of the bud which is to develop into the perithecium, in 

 so far as concerns its position with reference to the cells of the receptacle, is, as has 

 been previously mentioned, subject to many variations in the different genera, 

 although that which has just been described is the most common. The genus Amor- 

 phoinyces, to which reference has several times been made, presents the most essential 

 difference in this respect ; since the terminal and subterminal cells of the germinating 

 spore constitute the primordial cells of the procarpe and of the perithecium proper, 

 respectively ; the latter dividing and growing up around the former as in the case of 

 Stigmatomyces just described (Plate V, fig. 23, d, c). In several other cases, as in 

 Rhadinomyces and Enarthromyces (Plate III, figs. 13-18), the female organ first 

 appears as a free bud, developed from a cell, not necessarily the sub-basal cell, of the 

 receptacle ; and this bud having become divided by a cross partition into two super- 

 posed cells, the same changes w T hich have already been described in detail, take place 

 in essentially the same way, as will be presently noted. 



A very remarkable variation from the method above described by which the 

 primordia of the perithecia and sexual organs arise from the -receptacle, occurs in 

 Zodiomyces ; a genus in which these organs, instead of originating as superficial out- 

 growths, are formed as buds from a layer of cells which line the bottom of the cup-like 

 extremity of the receptacle. This cup-shaped portion, though open at maturity, 

 Plate XXIII, fig. 8, originates as a closed cavity below the base of the primary 

 appendage, fig. 5, x, which becomes open as a result of the destruction of the super- 

 ficial cells above it, which is effected by numerous sterile appendages that make their 

 way out, fig. 6, y. The cells which give rise to the perithecia are thus primarily 

 derived from the central parenchyma of the body of the receptacle. The course of 

 development of the perithecia, in this instance, does not appear, however, to differ 

 very materially from that already described. 



Apart from these differences in origin, the development of the female organ corre- 



