448 BOTANICAL GAZETTE [DECEMBER 
Fic. 149a. Portion of threads from fig. 149 under higher magnification. 
Fic. 150. Threads becoming arranged parallel to one another. 
Fic. 150a. Portion of threads from fig. 150 under higher magnification. 
Fic. 151. Synapsis. 
Fic. 151a. Portion of the parallel threads from jig. 151 fusing in parts, under 
higher magnification. 
Fic. 152. Nucleus emerging from synapsis. 
Fic. 152a. Portion of fused parallel threads or spirem from fig. 152 under 
higher magnification; the spirem beginning to split longitudinally. 
1G. 153. Later stage than the above; spirem beginning to segment to form 
chromosomes; the split segments arranged side by side. 
Fic. 153a. Segments of spirem from fig. 153 under higher magnification, 
showing xX and double t and vy forms. 
PLATE XXVIII. 
Fic. 154. Early prophase of mitosis in tetraspore mother cell; 20 bivalent 
chromosomes are present. . 
Fic. 154a. Chromosomes from fig. 154 under higher magnification, showing 
bivalent character. 
Fic. 155. Later prophase; bivalent chromosomes have been shortened. 
Fic. 156. Metaphase; a great number of chromosomes (about 80) arranged 
in the equatorial plate; this large number results from the premature division of 
the halves of the bivalent chromosomes shown in fig. 155; the 80 chromosomes 
are therefore granddaughter chromosomes, which will be distributed to the four 
tetraspores; centrosphere-like structures poorly differentiated. 
Fic. 157. Later metaphase of the first mitosis; two groups of daughter 
chromosomes, 40 in each, just separating and the four poles of second spindle 
already differentiated. 
Fic. 158. Metaphase of 1 mitosis; four groups of sade chromo- 
somes (three seen) passing to the poles. 
Fic. 159. Groups of granddaughter chromosomes at the poles; nucleolus 
has appeared in the center of se sun seat ease 
Fic. 160. Groups of g forming chromatin network; 
membrane surrounding the nuclear cavity assuming a tetrahedral shape with 
kinoplasm accumulating at the lings 
Fic. 161. G I formed an anastomosing 
chromatin network; membrane cana nuclear cavity has broken in the 
region between the four poles so as to admit the entrance of kinoplasmic fibrils 
without the membrane; the fibrils grow toward the center of the nuclear cavity. 
Fic. 162. Daughter nuclei becoming separated by the growth of kinoplasm 
which surrounds the chromatin network. 
Fic. 163. Tetraspore mother cell at the time of F separation of the daughter 
nuclei. 
