288 Beer.— On the Development of the Spores of Riccia glauca . 
9. The reduced number of chromosomes in Riccia glauca is either 
seven or eight, but it could not be decided with certainty between these two 
numbers. 
It will be noted that this number is considerably higher than that 
(four) recorded by Garber and Lewis in Riccia ( Ricciocarpus ) natans and 
R. cry st allin a . 
10. In the telophase of the division a number of chromatic bodies, 
which are no doubt derivatives of the chromosomes, are distributed upon 
the linin fibres. Subsequently these scattered bodies aggregate together 
to form the lobular nucleolus of the resting nucleus. 
11. The membrane, which is formed between the daughter - cells 
resulting from the first division of the mother-cell, does not at first extend 
to the periphery of the cell. 
12. At the conclusion of the second maiotic division the special- 
mother-cells are separated from one another by delicate membranes which 
have a pectose-cellulose composition. 
13. Upon these primary special-mother-cell walls secondary thickening 
layers are deposited which give the reactions of callose. This callose is 
directly deposited as such by the protoplast, and is not a transformation 
product of cellulose. 
14. The ( first spore-wall is a cuticularized structure from a very early 
period. No decisive data could be found to determine whether this wall is 
derived from the transformation of the innermost lamellae of the special- 
mother-cell wall or whether it is a new formation directly due to the 
secretory activity of the protoplast. It was shown that the arguments 
brought forward by previous writers are insufficient to prove the case either 
one way or the other. 
15. Within the first spore-wall at the equatorial rim a plug of mucilage 
is deposited. This mucilage, which gives the reactions of callose, has no 
direct relation either to the thickening layers of the special-mother-cell 
wall (as Leitgeb supposed) or to the first spore - wall (as Strasburger 
supposed). It is a new and independent formation. 
16. The second spore- wall is next formed within the first wall. It is 
cuticularized from a very early time, but there is reason to believe that 
previous to its cuticularization it reacts as a pectose-cellulose membrane. 
17. At first the second spore-wall appears to be quite homogeneous, 
but subsequently it can be seen to be composed of three parts:— 
(i) an external loosely laminated region ; 
(ii) a layer of dark-coloured material ; and 
(iii) an internal densely laminated region. 
The dark-coloured material appears to have been interpolated into 
a space which forms between the two laminated regions of the wall. 
18. The endospore, which is formed late in the development of the 
