44 BOTANICAL GAZETTE [JANUARY 
cover a condition where no chromatin centers are visible, but in 
which the chromatin units, or small groups of units, arising from 
the fragmentation of a single chromosome, exert a mutual attrac- 
tion and come together in a uniform body during the prophases. 
It is somewhat more difficult to apply this conception to the 
cases of nucleolar origin of chromosomes. Although little is 
known about the nature and structure of the nucleolus, it seems 
plausible that the same relations between chromomeres may exist 
whether they are inclosed in a comparatively small body, the 
nucleolus, grouped in several small bodies, the chromosomes, or 
scattered in the nucleus. 
An obstacle to the view of the persistence of either chromo- 
somes or smaller chromatin units arises, however, when we con- 
sider the recent work of certain authors, such as that of Miss 
Dicpy (10) on Galtonia candicans, or that of GATES (16) on Oceno- 
thera gigas. Miss Dicpy describes a condition in Galtonia in which 
chromatin buds off from the nuclear framework, synaptic knot, or 
nucleolus, and passes into the cytoplasm or even into ‘neighboring 
cells; these buds eventually disintegrate. Though Miss DicBy 
implies that the parent nuclei develop normally, she does not 
describe their development beyond the spireme stage. However, 
she cites cases where entire loculi contained aborted pollen mother 
cells. Gates describes a similar phenomenon in Oenothera gigas. 
During the synaptic stage there is an extrusion of a part of the 
chromatic matter of the spireme into an adjoining cell; the extruded 
portion degenerates, but the nucleus from which it came behaves 
normally. CARRUTHERS (6), in a description of the cytology of 
Helvella crispa, states that there are extrusions of chromatin-like 
material from the poles of the nucleus, which disintegrate in the 
cytoplasm and take up nucleolar stains. Grices (18) says, of the 
masses of chromatin in the nuclei of Rhodochytrium, a portion re- 
mains free and is cast into the cytoplasm or remains as beads on the 
spindle fibers, while the rest of the chromatin forms the chromosomes. 
It is also not without interest to recall the condition of Spirogyra 
(BERGHS 3, MITZKEWITSCH 27) where a chromatic nucleolus dur- 
ing the anaphase shows tiny chromosomes enveloped in its mass; 
at the metaphase the nucleolus is divided and the halves move 
