On the development of the Sporce of Anthoceros laevis. 85 



condensed at the circumference of these granular masses, 

 forming an almost circumscribed cavity, exhibiting in this 

 manner as it were almost globular cells filled with green 

 granules. Towards the exterior the walls of these cellules 

 are however not completely evident, but they pass immedi- 

 ately into finely granular mucilage. 



Now each of these granular masses, which I shall de- 

 signate by the name of granular cellule, is divided into two 

 distinct parts, in such a manner that in all there are four. 

 First these four cellules are placed by the side of each other 

 (figs. 18, 19, 20,); but they separate, approximate the wall of 

 the mother-cellule, and assume the position of the four angles 

 of a regular equilateral tetrahedron (fig. 21, 22). 



The mucilaginous mass in which the granules are placed 

 becomes equally divided, and each of these parts become 

 enveloped by a particular atmosphere which is thin and 

 mucilaginous. The principal part of the colourless mucilage 

 becomes changed, on the other hand, into fibrous threads, 

 which direct themselves from one granular cellule to ano- 

 ther. The nucleus (figs. 2\, 22), which at this period ap- 

 pears always to diminish in volume, is found placed at the 

 centre of the mother-cellule and of the mass formed by the 

 fibrous filaments, is absolutely distinct from the four granu- 

 lar cellules. 



During the time that the contents of the mother-cellule 

 exhibit those mutations, the wall changes equally ; originally 

 this part was formed of a thin membrane, which was very tena- 

 cious, however since the period when the green granular mass 

 became divided in two, the wall of the cellule became more 

 and more thick, (figs. 15, 17, 18, 19, 2\, 22). 



When the granular cellules are placed close to the wall of 

 the mother-cellule it frequently happens that the wall does 

 not present an equal thickness, but in certain places becomes 

 swollen more than in others (fig. 21.) At this period the mo- 

 ther-cellule is not only become larger, but its form, at first 



