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other close to the first of the neck canal-cells. Meanwhile these 

 latter degenerate, i.e. their walls disappear and they become some- 

 what rounded, so that they lie detached in the neck. 



The top of the neck opens and through the opening the neck 

 canal-cells pass out. This could be seen in living specimens with 

 mature archegonia; when they were placed in water, the neck soon 

 opened and the cells appeared one by one. 



At the stage when the neck-cells have become separated and the 

 neck itself is about to open, a large number of the neck-cells may 

 be found, in fixed preparations, in the venter of the archegonium. 

 They lie loose round the ovum and the ventral canal-cell. 



The ventral canal-cell now approaches the ovum and applies itself 

 to the latter. No demarcation between the cytoplasm of the two cells 

 can then be observed. The two nuclei lie side by side and gradually 

 fuse. This was observed by us several times and in all the successive 

 stages. The rest of the ventral canal-cell shrivels up and is extruded 

 like the neck canal-cells. 



Finally the ovum lies by itself in the venter with a large, normal, 

 round nucleus. 



A transformation of the neck canal-cells into mucilage, as described 

 by Gayet l ) and others, does not occur. Mucilage may indeed be 

 found later in the neck, and may serve to attract spermatozoids, 

 but it is probably secreted by the neck-cells themselves. 



It now became of great importance to know the number of 

 chromosomes in the nucleus of the ovum. Unfortunately, as has 

 already been remarked, only a very limited number of nuclear 

 divisions can be found in the tissues of Mosses, (except in the anthe- 

 ridia) and hence most of the ova were either in a stage before, or 

 in a stage after that of nuclear division. In the other dividing cells 

 of the archegonium there were always six chromosomes. At the stage 

 immediately preceding mitosis, the nucleus of a young cell, which 

 after division would form an ovum, showed six pieces of chromatin. 

 Happily we found one very good mitotic stage. Here there was a 

 large spindle, parallel to the axis of the archegonium, which proved 

 that we had lighted on the division of the egg mother-cell. There 

 were six chromosomes, and though they were still in contact witli 

 each other in pairs by one end, the other end was already directed 

 to the top of the spindle. It was highly probable, that of the six 

 chromosomes three were going to one and three to the other pole. 

 The discovery of a nuclear fusion also leads to the supposition, that 



i) L. Gayet. Ann. des Sc. nat. Bot. Série 8, T. III, 1897. 



