Black . — The Morphology of Riccia Frostii, A test. 523 
characteristic of the chromosome is that in larger cells the chromosomes 
are longer and comparatively slender, while in smaller cells they are short, 
thick rods, with a slight curve, as shown in PI. XXXVII, Fig. 24, and 
PI. XXXVIII, Figs. 49 and 51. Fig. 48 shows two adjacent cells in 
metaphase. No stage was found showing the chromosomes on their way 
to the poles. Figs. 55 and 56 show stages in late telophase. 
The cells, previous to the diagonal division, were examined with par- 
ticular reference to centrosome-like bodies. Frequently a spindle would be 
found with rather significant bodies at either pole, as represented in Fig. 48. 
Other granules, however, were found scattered through the cytoplasm, and, 
since optical phenomena would naturally make granules in a polar position 
appear more distinct, the presence of a definite body at the poles was 
considered doubtful in prediagonal mitoses. 
The Diagonal Division. 
The spermogenous cell previous to the last division is extremely small. 
With successive divisions in the spermogenous tissue the cells become 
smaller, and finally the oblique division is initiated. The nucleus (Fig. 57) 
is so small and stains so deeply, that little chromatin can be distinguished 
in it. No bodies at the poles could be demonstrated. But in Figs. 58 and 
59 the nucleus is found to be elongated in the direction of the diagonal axis 
of the cell, and at either pole is a definite body. Frequently more than 
one granule was found at or near the poles. These granules are apparently 
of kinoplasmic origin, and are no doubt a response to the same stimulus that 
is later realized in the blepharoplast, although not necessarily a definite 
phase in the development of the blepharoplast. The chromatin consists of 
a few scattered lumps, the forming chromosomes. The spindle is eventually 
formed, with a body at each pole (Fig. 60). The chromatin is collected at 
the equator, and in Figs. 61 and 62 the complete spindle is diagonally 
placed in the cell with the bodies terminating the axes. Polar views in 
Figs. 63 and 6 4 show the short curved chromosome. 
Many spindles were seen in which it was impossible to distinguish 
a body at the poles, even with repeated staining. No stage was found 
showing the telophase or construction of the daughter nuclei. If a cell 
plate is suggested it does not persist, as the triangular cells resulting from 
the last division are found enclosed in the wall of the sperm mother-cell, 
with no wall separating them (Fig. 66). The polar granules disappear with 
the completion of the mitosis (Fig. 65). No evidence was found that they 
persist in the final oblique division, becoming the blepharoplasts. 
There appears in these triangular cells a definite body, much more 
definite than the one discussed previously (Fig. 67). This body may occur 
in opposite angles of the two cells or in the same angle (Figs. 66 and 68). 
About this time the cell-walls break down and the triangular cells are free. 
