Species of Olpidiopsis ) (Cornu) Fischer . 225 
dense, rather large masses of chromatin, which are surrounded by nuclear 
hyaloplasm. 
Successful examination of the histology of the resting spores was 
impossible. Dangeard observed that the dark zone of colourless protoplasm 
about the developing spore hindered observation. He states that they are 
multi nucleate. 
Concerning the study of the second species, O. Aphanomycis , Cornu, 
nothing of importance was added. Dangeard observed a spiny resting 
spore without a companion cell, which would place this species in the genus 
Pseudolpidium as P. Aphanomycis. 
B. Sporangia. 
Fig. 31, PI. XXIV, represents a young parasite soon after its entrance 
into the host. It is uninucleate, much vacuolated, and not unlike Fig. 35, 
which is a zoospore from a discharging sporangium. The protoplasm, which 
is finely granular, exists in the form of a parietal layer. Growth of the 
individual has not proceeded far until the single nucleus divides. 
Fig. 32 shows the binucleate stage. The nuclei are prominent and 
contain large deeply staining bodies which are presumably nucleoli. As is 
seen in Fig. 33, the nuclei divide mitotically. Fig. 34 is a section through 
a slightly older individual, showing three of its four nuclei and the very much 
vacuolated and granular nature of the protoplasm. It is assumed, from the 
condition of the protoplasm, that it is about this time in the life of the 
individual that it becomes lost to view in the host. 
Nuclear divisions proceed rapidly, and we soon find the condition 
shown in Fig. 36. It will be observed that the protoplasm lies principally 
in the peripheral layer, in which are embedded the many still prominent 
nuclei. There is also observed a tendency for small granules to collect 
about the outside of the parasite, indicating, perhaps, the beginning of the 
formation of a wall, as a very little later one finds that a thin wall has 
developed. The large irregularly shaped fat bodies observed in the living 
specimens are in most cases not visible in stained sections. 
Following the condition shown in Fig. 36, there is a gradual inward 
growth of the protoplasm, accompanied by an increase in size of the parasite 
and a continued rapid nuclear division. A little later the sporangium is 
almost filled with fine granular protoplasm in which are distributed a few 
large and numerous small irregularly shaped vacuoles. Fig. 37 represents 
a section of a small sporangium at that period of development with its 
nuclei undergoing their last division. The sporangial wall is very distinct 
and the sporangium has probably reached its maximum size. The large 
vacuoles have become regular in outline and at the same time the smaller 
ones show less distinctly. 
Q 
