i6o 
Lloyd Williams . — Studies in the Dictyotaceae . 
Fig. 1 8, #, <5, r ( Padina .). Three sections of the same nucleus, showing the reduced number of 
chromosomes, all of which except one are uncut. 
Fig. 19. The chromosomes reduced in size and ready for being placed on the spindle. A few 
spindle-fibres have already appeared, and the nucleolus is breaking up into fibrillae. 
Fig. 20. Intranuclear spindle with mantle-fibres and nucleolar fibrillae. (The globule is in 
another section.) The chromosomes are heterotype in character. 
Fig. 21. A slightly oblique section, showing more clearly the form of the chromosomes. The 
number is sixteen, but those in a lower focus have not been drawn. 
Fig. 22. One of the poles of the preceding figure, showing the curved rod-like centrosome. The 
section containing the other pole is very similar. 
Fig. 23. One of the two daughter-nuclei of the first division. There is a large mass of fibrillar 
chromatin and a small nucleolus. 
Fig. 24. A later stage. The chromatin becomes distributed through the nucleus and the nucleolus 
increases in size. 
Second Division in the Tetraspore Mother-Cell. 
Fig. 25. Early prophase. Nucleolus swollen, irregular, and fibrillar. The section is transverse 
to the nuclear axis. 
Fig. 26. A number of short curved chromosomes have appeared, and the nucleolus is irregular 
and fibrillar. 
Fig. 27. Spindle. The polar radiations are directed towards those of the sister-nucleus, the 
membrane on the inner side is intact, the spindle being on the opposite side. A nucleolar globule 
is present. 
Fig. 28. Anaphase stage. The nuclear cavity is much narrower and curved. The chromosomes 
though small show no signs of fusion. 
Fig. 29. One of the four nuclei of the sporangium before spore differentiation. 
The First Division in the Germinating Tetraspore. 
Fig. 30. Prophase. Very coarse spirem and fibrillar nucleolus. 
Fig. 3T. Spindle with curved chromosomes (one has lagged behind). There are two sections 
of this, and the number of chromosomes in the two together is sixteen. The radiations are distinct ; 
there is no globule. 
Fig. 32. Anaphase stage. Membrane still intact at the sides. 
Fig. 33. 1 Dispirem ’ stage. The nucleolar membrane projects towards the very distinct 
centrosome. 
Fig. 34. Polar view of daughter-nuclei before fusion of chromosomes. About sixteen may be 
counted. Near the bottom of the figure a small body staining differently to the chromosomes 
is seen. This is probably the beginning of the nucleolus. 
Fig. 35. A later stage than Fig. 26, where a chromatin mass, a nucleolus, and a reticulum have 
been differentiated in each daughter-nucleus. 
