Bic) 2 
of the two moieties is not sufficient (besides reasons based on morpho- 
logical grounds) to warrant the interpretation of a compound nucleolus, 
i. e., a combination of plasmosome and chromatin nucleolus. 
In synizesis also the fate of this nuclear element is different from 
that of the usual chromatin or chromosome nucleolus (accessory 
chromosome). At least in the great majority of cases it does not 
take position within the synizesis mass, next the idiozome. Rarely 
it may be here — since it can be detected nowhere else — occasionally 
it lies to one side close to the mass (figs. 11 and 12), but usually it 
lies opposite the attached or idiozome pole and more or less clearly 
connected to the main mass (figs. 7, 8 and 9). The connecting link 
in this case is a delicate chromatic thread. As in the resting spermato- 
Description of Illustrations. 
(All illustrations are magnified 1800 diameters.) 
Fig. 1. Metaphase plate of chromosomes of dividing spermatogonium. Most of 
the chromosomes are already longitudinaly split. Scattered among the chromosomes 
are many spherical, more or less chromatic, mitochondria (chromidia) of various sizes, 
apparently of chromosomal origin. Stippling indicates lighter or les chromatic character. 
The protoplasm (not indicated) is of the granulo-alveolar type. 
Figs. 2 and 3. Metaphase and telophase stages respectively of dividing spermato- 
gonia, with numerous mitochondria, from same follicle as fig. 1. The close association 
between the spermatogonial chromosomes during mitosis and the mitochondria (and their 
earlier absence) indicates a chromatin (chromidial) origin of the latter. 
cyte, the pipartite body may occasionally be represented by two ele- 
ments (products of separation), so during synapsis two similar bodies 
may in some instances be present (fig. 10). 
This same body may still be recognized during early prophase 
of the first maturation mitoses (figs. 14 to 19) — usually attached to 
the spireme or one of the resulting chromosomes — but thereafter it is 
permanently indistinguishable among the chromosomes of the maturation 
mitoses. 
29% 
core) 
