Laboulbenia chaetophora and L. Gyrinidarum. 341 
The chromosomes appear to divide transversely (PL XXXIX, Fig. 52) 
and, as they approach the poles of the spindle, show a tendency to split 
(Fig. 53). They are not homogeneous, for as seen in cross-section they do 
not stain uniformly. The centre may be hollow, at all events it is much 
lighter than the periphery. Fig. 53 presents some interesting features 
and is interpreted as follows : The chromosome at the extreme right is 
dividing transversely, the large one in the centre is still entire, the two 
pieces at the left are segments of the third chromosome, the uppermost 
is a daughter chromosome splitting, and portions of its sister, also 
longitudinally split, are on their way to the opposite pole. 
The asters in the anaphase stage are even more distinct than earlier. 
A vacuole gradually forms around each of the chromosome masses, and 
the daughter nuclei very soon stand out clearly defined. 
The second mitosis follows very swiftly on the heels of the first and 
is essentially different in many details. There is no preliminary synapsis 
stage, the spindle is sharper pointed, the central bodies are smaller, the 
chromosomes split longitudinally (PI. XL, Fig. 55), the spindles are not 
differentiated as is the first, and there is no subsequent elongation. As 
a result of this the daughter nuclei lie side by side. Fig. 57 represents 
a tetranucleate stage of the ascus, showing the two pairs of sister nuclei. 
The four nuclei now pass through a brief resting period, during 
which the chromatin is in the form of threads, and possibly in connexion 
with the persistent central bodies (Fig. 57). 
During the prophase of the last mitosis the relation of the chromatin 
to the central bodies is more evident (Fig. 58). Presumably the latter 
divide, constituting the poles of the spindle on which four chromosomes, 
corresponding to the four threads of the prophase, take up a position in the 
equatorial plane (Fig. 59). It was not possible to determine just how the 
chromosomes divide, but they do divide, and there is no reduction in 
their number (Figs. 60, 61). Nor was it possible to detect a differentia- 
tion in the spindle, which, whatever its constitution, is extensible, since the 
daughter nuclei are carried far apart (Fig. 62). The astral rays are long 
and tenuous. They are represented in Fig. 62 just before the spores are 
delimited, and again in Figs. 63 and 64 after this process is completed. 
That they do not fuse laterally and do not form a part of the limiting mem- 
brane is perfectly obvious, even were such a phenomenon as lateral fusion 
physically possible. 
The spores are delimited progressively, beginning always at the 
central body. Relative to the process nothing more can be added than 
has already been described by the author and corroborated by P'raser and 
Brooks (’ 09 ) and Brown (’ll), and in part by Dangeard (’ 07 ). Faull (’ 05 ) : 
The spores are delimited £ by the differentiation of a limiting layer of 
hyaline or finely granular layer of protoplasm that begins adjacent to the 
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