14 HOFMJEISTER, ON 



in other parts of the fruit. Measured vertically, one cell 

 of the columella, or two of the wall of the fruit, are equal 

 to at least four of the cells of the latter layer (PL III, fig. 1). 

 The wall of the fruit is thinnest in its upper part. It con- 

 sists there of only four layers of cells, whilst towards the 

 base there are five such layers (PL III, fig. 1), being the 

 result of the division of the cells of the second layer (reckon- 

 ing from without inwards) by longitudinal septa parallel 

 to the longitudinal axis of the fruit. 



Those cells of the layer surrounding the columella which 

 are destined to be the mother-cells of spores become 

 detached from the neighbouring cells, and assume a spheri- 

 cal form. Their contents consist of finely granular proto- 

 plasm, and a large central transparent nucleus with a large 

 nucleolus (PL III, figs. 1, 3). Those destined to form 

 elaters remain less developed. Their nucleus disappears ; 

 in its place are seen two new nuclei, between which a 

 septum is produced, dividing the cell into two daughter- 

 cells (PL III, fig. 1 l ). The same process recurs in one, 

 sometimes in both, of the newly formed cells ; so that the 

 fully grown elater consists of a row of three or four cells. 



The perfecting of the spore-mother-cells proceeds slowly 

 from the upper to the lower part of the fruit. A well- 

 made longitudinal section of a half-ripe fruit exhibits a 

 graduated series of all the different states, from the first 

 separation from the neighbouring cells up to the formation 

 of the spores. The spore-mother-cell increases rapidly in 

 size after becoming detached from the neighbouring tissue. 

 The protoplasm in its interior divides into strings, radiating 

 from the nucleus, and into a thin parietal layer (PL III, 

 fig. 4). Shortly afterwards an accumulation of mucilagi- 

 nous plasma is formed close to the primary nucleus which 

 occupies the middle point of the cell. This plasma, in 

 Anthoceros lavis, is usually coloured green by the particles 

 dispersed in it ; in A. pimctatus it is colourless. This 

 accumulation divides itself into two halves, each of which 

 clothes one of the poles of the globular nucleus (PL III, figs. 

 5, 5''). In slightly older cells, tw T o newly formed second- 

 ary nuclei are found near the primary nucleus, surrounded 

 by a halo of finely granular protoplasm, from which strings 



