EXPLANATION OP PLATE 12 



Trichomitus parvus geu. nov., sp. nov. 



All figures from preparations fixed with hot Schaudinn 's fluid and stained 

 with iron haematoxylin, drawn with camera lucida and Zeiss 2 mm. apochro- 

 matic oil immersion. X 2583. 



Fig. 1. Trophozoite, showing nucleus, blepharoplast, three anterior and one 

 posterior flagella and undulating membrane with its chromatic margin and 

 chromatic basal rod or parabasal body. 



Fig. 2. Large trophozoite, showing variation in size. 



Fig. 3. Trophozoite, showing variation in nuclear structure (central karyo- 

 some). 



Fig. 4. Prophase of division; with splitting of the blepharoplast and out- 

 growth of one new flagellum. 



Fig. 5. Prophase with the daughter blepharoplasts on opposite sides of the 

 nucleus, spireme formation of the chromatin, and extra-nuclear paradesmnse. 



Fig. 6. Slightly later stage of the same. 



Pig. 7. The same stage, with possibly a differentiation of the chromatin 

 into (splitting?) chromosomes. 



Fig. 8. End of prophase with chromatin massed at the center of nucleus. 

 ' ' Amphiaster ' ' stage. 



Pig. 9. Telophase with two chromosomes bound to the blepharoplasts by 

 short fibrils: outgrowth of full complements of flagella. 



Fig. 10. Later stage, showing reorganization of nuclei: note persistence of 

 paradesmose connecting daughter nuclei and blepharoplasts. 



Fig. 11. Stage preparatory to final separation of the daughter organisms. 



Fig. 12. Second division of the nucleus in process of multiple fission. 

 Division not synchronous. 



Fig. 13. Eight-nucleated somatella, showing division of nuclei completed, 

 each with full set of organelles. 



Fig. 14. Stage in plasmotomy showing four-nucleated organism. 



Fig. 1-5. The same, showing variation in size. 



Fig. 16. Three-nucleated somatella. 



Fig. 17. Final stage in plasmotomy. 



[94J 



