STRUCTURE AND LIFE-HISTORY OF COPROMONAS SUBTILIS. 119 
Heidenhain’s iron hematoxylin; drawn under a 3 mm, apochromatic oil-immer- 
sion, compensating ocular 18. 
Vic. 1.—Copromonas subtilis—adult individual before division. 
Fie. 2.—Same individual, drawing in flagellum preparatory to division. 
Fic. 3.—The same; flagellum completely drawn in, and nucleus dividing. 
Fie, 4.—Still later; two new flagella growing up side by side, nucleus in 
later stage of division, ete. 
Fre. 5.—Later ; nucleus and reservoir divided ; growth of new flagella, etc. 
Fig. 6.—Stained preparation, showing chief anatomical features. 
Fries. 7-10.—Various consecutive stages in division. 
Fires. 11-16.—Conjugation. 
Fig. 11.—Attachment of two monads by their anterior ends. 
Fic. 12.—The same, twenty-five minutes later. One flagellum has been 
drawn in. 
Vre. 18.—The same, thirty minutes later, 
Fie. 14.—Filteen minutes later. 
Fic. 15,—Twenty minutes later; monads almost completely fused. 
Fic. 16.—Fifteen minutes later. Complete fusion has taken place, and 
the resulting zygote has become re-modelled to the form of an ordinary 
individual. 
Fics. 17-19,—Various forms of cyst met with in cultures. 
Vie. 20.—Monad shortly after liberation from cyst. 
Fies. 21-33.—Conjugation and encystment. 
Fig. 21.—Fusion of two individuals ; one flagellum is being drawn in. 
Vie. 22.-—Further fusion has taken place; only one flagellum present. 
Fic, 23.—First nuclear reduction. On the left, nucleus in an early stage 
of division (cf., Plate 5, fig. 35); on the right, nuclei almost divided. 
Fie. 24.—The reduction nuclei have been formed, and are degenerating. 
They are pale and situated below the gamete nuclei. (This specimen is 
slightly flattened.) 
Fie. 25.—Further nuclear reduction by heteropole division (granule extru- 
sion). Parts of the first reduction nuclei are seen degenerating below. 
Fic. 26.—Later stage, containing two reduced gamete nuclei. 
Fic. 27.—Nuclei fusing; zygote assuming motile monad form. 
Figs. 28-30.—Fusion of nuclei and encystment. 
Fie. 31.—Descendant of zygote monad before encystment. 
Fic. 32.—A similar organism at a later stage. 
Fic. 33.— Resting cyst ; formed from either 30 or 32. 
