NEUROSPORIDIUM. 99 



PLATE 7. 



All the figures on Plate 7 were outlined with camera lucida (Abbe), usiug 

 apochromatic objective 3 mm. homogeneous immersion (Zeiss) and compen- 

 sating oculars 4 and 8. 



All the figures of this plate, except fig. 16, are enlarged 1000 diameters. 



Significance of the Lettering. 

 cati. The cavity in the host tissue in vphich the parasite lies; it often con- 

 tains a coaguluni {coag.). chr. Chromidia or daughter-nuclei resulting from 

 the division of the nucleus of the spore-morula in the formation of spores, 

 principally those daughter-nuclei remaining over in old and degenerating cap- 

 sules, cps. Capsule, an ill-defined, sometimes alveolated membrane around 

 the parasite ; it is not a true cyst, and is apparently formed by the tissue of 

 the host. cps'. A similar layer lining the healthy tissue of the host. nu. 

 Nucleus (figs. 4 to 9), or daughter-nucleus (figs. 12 to 14). p'spbl. Pan- 

 sporoblast, r.n. Residual nucleus of the spore-morula. r.sp.m. Residual 

 cytoplasm of the spore-morula. vac. Vacuole. 



Pig. 3. — A number of free spores, a. An amsebula, with one nucleus. 

 b and d. Later stage, young trophozoites with two and three nuclei respec- 

 tively, e sliows nuclear division, rather indistinctly, but as well as could be 

 expected from the material to hand. 



Fig. 4. — Deeply staining spore (amsebula) lying in a definite cavity in the 

 nervous tissue of the host. 



Pig. 5. — Several such spores in a cavity, surrounded by a thin envelope 

 {cps'.). 



Pig. 6. — Several young trophozoites lying in a cavity. 



Pig. 7. — Young trophozoites coalesced into a plasmodium, lying in a cavity, 

 with another young trophozoite, which examination of the series of sections 

 shows to be continuous with it. A coagulum is also seen, probably resulting 

 from the remains of the host cells. This specimen is in the stage of pansporo- 

 blast formation. Although smaller than those shown in figs. 8 and 9, it is in 

 a later stage of the life cycle. 



Fig. 8. — Multinucleate trophozoite or "plasmodium." 



Pig. 9. — Multinucleate trophozoite, surrounded by a capsule, lying in a 

 cavity in the host tissue. 



Pig. 10. — Elongate trophozoite, with oval pansporoblasts lying in deeply 

 staining granular protoplasm. There is also a small trophozoite by the side, 

 lying in the same cavity. 



Fig. 11.— Ovoid trophozoite, full of pansporoblasts. 



Pig. 12. — Several spore-morulse (full-grown, segmenting pansporoblasts), 

 which are dividing into spores. The parasite is seen surrounded ill- 



