MONOGKAI'll OF THE LABOULISKNI ACK .E. 



221 



In brief, then, we find the female organ developed at first as a lateral outgrowth 

 from one of the cells of the receptacle. From this outgrowth a terminal and ;i sub- 

 terminal cell are cut off. From the former of these by further division is produced 

 the procarpe, consisting of a terminal receptive portion, the trichogyne, a middle con- 

 necting portion, the trichophoric cell, and a lower essential portion, the carpogenic 

 cell, which alone develops further; while from the latter arises by further division the 

 whole of the perithecium proper. The subterminal cell thus forms the basal and 

 wall-cells of the perithecium, while the terminal one, although at first quite free, 

 forms its contents. 



The further development of the young perithecium after the fertilization of the 

 trichogyne may be also best illustrated by reference to the same series of figures of 

 Stigmatomyces (Plate I, figs. 17-24). In fig. 17, which represents a condition in 

 which fertilization has been completed, the procarpe remains unchanged, except that 

 the carpogenic cell (/) has become somewhat enlarged and elongated. In fig. 18, the 

 first indications of development are seen in the carpogenic cell, which, through the 

 formation of two transverse partitions, has become divided into three superposed 

 cells, while the trichogyne has begun to wither. As a rule, however, it has entirely 

 disappeared when the first divisions of the carpogenic cell are visible. In fig. 19, this 

 division of the carpogenic cell has become still more pronounced, and nothing remains 

 of the trichogyne but its insertion. Disregarding the accompanying development of 

 the wall-cells of the perithecium, and following only the divisions of the carpogenic 

 cell, we may distinguish the three cells into which it first divides as follows: the 

 lower of the three (is) may be termed the inferior supporting cell, while the upper con- 

 stitutes the superior supporting cell (s s). The remaining cell, which lies between the 

 two, may be conveniently termed the ascogonium (am), and is the only one of the three 

 which undergoes any further development ; the two supporting cells eventually dis- 

 appearing entirely. Up to this point the development of the procarpe is similar in 

 all the genera, so far as they are known ; but the further divisions of the ascogonium 

 show certain variations in different genera and even, apparently, in different speci- 

 mens of the same species, although it is improbable that individual variations of this 

 nature are at all common. In the present instance the ascogonium divides into a 

 lower and an upper portion, the latter at the same time dividing, by somewhat irregu- 

 larly longitudinal septa, into four cells. The lower portion (figs. 20-23, is t) remains 

 unchanged, being eventually destroyed, like the two supporting cells (ss and is), and 

 may be called the secondary supporting cell. We have then the ascogonium dividing 

 simultaneously into five cells, one of them, the secondary supporting cell, remaining 



