342 XXV. REPRODUCTION OF THE BRYOPHYTA. 



comparatively minute,^have a thread-like body and two long cilia ; 

 to the posterior end clings a vesicle, which is lost during the 

 swarming. In order to see them clearly, we run into the 

 preparation a drop of 1 per cent, osmic acid, and as they 

 are fixed beautifully by the reagent, we can now study them 

 conveniently (Fig. 123, B), or we can use for the same pur- 

 pose a trace of iodine solution. The cilia can be seen with 

 especial clearness in dry preparations, which are obtained 

 by allowing a fresh preparation, or one which has been 

 fixed in any way, to dry slowly and perfectly without covering 

 it with a cover-glass. Such preparations can then be covered 

 with a cover- glass, and can be closed in any suitable way and 

 preserved. 



The female receptacle forms, like the male, a radially- 

 spreading inflorescence ; and in general there are nine rays, and 

 between them are eight rows of archegonia on the under side 

 of the receptacle. The distinction from the male receptacles is 

 striking, in that here the sexual organs stand upon the under side ; 

 but this phenomenon is connected with an early displacement of 

 the growing point towards the under side of the receptacle. 

 Under the simple microscope we can demonstrate that each row 

 of archegonia, lying between two rays, is enclosed in a common 

 veil-like covering, fringed at its edges. We prepare, between 

 thumb and forefinger, delicate longitudinal sections through a 

 comparatively young receptacle, and upon some of these sections 

 find, without difficulty, the female sexual organs, the archegonia. 

 The oldest lie nearest the edge, the younger progressively nearer 

 the stalk. The first ripening archegonia show along the edge 

 of the disk with their neck curved upwards, the succeeding ones 

 hang straight down. In an approximately ripe archegonium 

 (Fig. 124, A) we can distinguish a short stalk or foot, a ventral 

 portion, the venter, and a neck. The wall of the venter, as of 

 the stalk, is unilamellar. The central cell of the venter is filled 

 by the oosphere, and the ventral canal-cell (&"), which is cut off 

 from it shortly before ripening. In the oosphere the nucleus 

 is readily visible. The neck is traversed by the neck-canal, 

 which is composed of a series of four neck canal-cells, the walls 

 between which are dissolved, and the disorganised contents thus 

 fused into a connected string. Between the archegonia arise 

 numerous small leaf-like scales of the receptacle. In many pre- 

 parations we can see the unilamellar veil-like covering, fringed 



