16 ERNEST WARREN. 



Fig. 3. — X 2000 diameters. Trophozoite undergoing fission at tlie 

 place of constriction. The trophoplasni is vacuolated, and granules 

 (s. gr.) are beginning to appear in it. 



Fig. 4. — x 2000 diameters. Trophozoite in which all the nuclei are 

 preparing for division ; the nuclear membrane is disappearing {d.n. m.), 

 and the chromatin is becoming concentrated around the periphery oi 

 the karyosome (n. d.). Ectosarc and endosarc are distinguishable. 



Fig. 5. — x 300 diameters. A series of young trophozoites, all taken 

 from one host. These exhibit the phenomena of plasmotomy both in 

 the form of fission and of budding. 



Fig. 6. — x 2000 diameters. Older trophozoite with numerous large 

 and small granules (J. gr. s. gr.) in the endosai'C. The nuclei are just 

 passing into a resting-condition, the nuclear membrane {n. m.f.) is being 

 formed. 



Fig. 7. — x 2000 diameters. A portion of a nearly full-grown tropho- 

 zoite. Nucleus has a well-marked nuclear memljrane and karyosome. 

 It should be noticed that the nuclei in the adult stage are not more 

 than half the size of those in the younger trophozoites (Figs. 1 — 6). 



Fig. 8. — X 2000 diameters. A portion of a full-grown trophozoite. 

 The trophoplasni is densely crowded with granules (gr.). The karyosome 

 of the nucleus has swollen, and the nuclear membrane has disappeared. 

 The nucleus is surrounded by a layer of clear protoplasm containing no 

 granules (c.a.). The opaque trophozoite is now in a preparatory con- 

 dition for the formation of spores. 



Fig. 9. — -x 2000 diameters. Section through trophozoite, showing 

 the formation of the trabecular {t. and t.f.). The whole of the tropho- 

 plasni had not become involved {iin.ji.) at the time of killing and fixing 

 the specimen. In several of the areas two nuclei can be seen ; doubtless 

 these would subsequently have divided. Each area will produce one 

 spore. The nucleus is without nuclear membrane ()«.), and the chromatin 

 is concentrated towards the periphery. 



Fig. 10. — X 2000 diameters. Surface view where the whole of the 

 trophozoite has been converted into spores. 



Fig. 11. — X 5500 diameters. Surface view, still further enlarged ; 

 the spores are nearly ripe, and ai'e seen to contain a "' vacuole " (v.) and 

 small nuclei (».). 



Fig. 12. — x 1100 diameters. Elongated trophozoite surrounded by 

 a thick cyst (cy.). The trophoplasm is beginning to be divided up by 

 trabeculse (t.f.). The two ends (un.p.) are still undivided, thus some- 

 what recalling the condition seen in Sarcocystis. 



Fig. 13. — X 2(X)0 diameters. R(junded encysted specimen with ripe 

 spores. 



