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stages of the formation of the embryosac in Vittadinia, seemed 
however to warrant a somewhat detailed study. 
The following are the results of this study. 
As far as I have been able to ascertain, the archesporium in 
Vittadima is as a rule unicellular (fig. 1). Only in one instance, 
two fully developed embryo sacs were seen twisting around 
each other, thus indicating two archesporial cells. The embryo sac 
mother cell remains for rather a long time in synapsis, increasing 
Vittadinta triloba. Fig. 1. Embryosac mother cell. — Fig. 2. Dyad stage; no 
wall formed between the daughter nuclei. — Fig. 3. Tetrade with the four nuclei 
separated only by vacuoles. — Fig. 4. Embryosac with two nuclei; the two 
degenerating megaspore nuclei at tbe basis, — (Leitz ok. 4; obj. imm. 1/12). 
slightly in volume. My material unfortunately, was not favourable 
for working out any cytological details; because of the lack of 
proper stages the chromosome number in the tretrad division 
could not be determined. : 
The reduction division stages are passed very rapidly and 
therefore all consecutive stages have not been seen, but the 
examination of a great number of slides has nevertheless given 
quite plainly a picture of the succession of stages. ; 
In the heterotypic division two daughter nuclei are formed, 
