Opalina. 369 
Fig. 191. A section of a zygote from a tadpole of Bombinator pachypus, 
infected 64 hours. The membrane between the two nuclei is broken down in the 
middle. Coros. subl.-acetie acid, Denarieny’s haematoxylin. >< 990 diameters. 
Fig. 192. A zygote, with nuclei marly fused, from a tadpole of Bombinator 
pachypus, infected 7'/. days. The nuclear structure was not clearly seen. Acetic 
acid. 673 diameters. 
Fig. 193. A zygote from a tadpole of Bombinator pachypus, infected 7'/, days. 
Acetic acid. < 673 diameters. 
Figs. 194—196. Zygotes from tadpoles of Bombinator pachypus, infected 
respectirely 4°/, days, 5 days, 4°/, days. Each nucleus (syncarion) shows eight 
chromosomes. In the nucleus shown in Fig. 196 were two structures, of different 
refractive quality from the chromosomes, which may have been nucleoli or vacuoles, 
probably the latter. Figs. 194 and 196 acetic acid; Fig. 195 acetic-carmine. 
x tO diameters. 
Figs. 197—200. Zygotes formed by the fertilization of binucleated macro- 
gametes. In each case the nucleus from the male lies between the two macro- 
gamete nuclei. In Figs. 198—200 it is evident that the nucleus from the male 
will fuse, or is fusing (Fig. 2(0), with the anterior of the macrogamete nuclei. 
The first is an acetic acid preparation, the others are acetic-carmine preparation, 
from tadpoles of Bombinator pachypus, infected respectirely 7 days, 136 hours, 
88 hours, 88 hours. Figs. 197, 199, 200 673 diameters; magnification of Fig. 198 
not recorded. 
Figs. 201—203. Binucleated zygotes, the anterior nuclei all being syncaria 
as is shown by their size and the number of their chromosomes. From tadpoles 
of Bombinator pachypus, infected 7 days. Acetic acid. > 673 diameters. 
Fig. 204. A zygote formed by the union of a male with a binucleated female 
whose nuclei were in a telophase of mitosis. The nucleus from the male is also 
in mitosis. The radiations at its two ends are merely films of the cytoplasmic 
foam (compare the next figure). From an acetic-carmine preparation; this animal, 
however, lay in a part of the slide where only the acetic acid, and not the carmine, 
had taken effect. The preparation was very clear. From a tadpole of Bombinator 
pachypus, infected 106 hours. > 673 diameters. 
Fig. 205. An optical section through the same animal, showing on a larger 
scale the nucleus from the male and the cytoplasm surrounding it. The nucleus 
lies in a vacuole of the cytoplasm, which it completely fills, its membrane being 
covered by a film of cytoplasm from which radiate other films. Where the radiating 
films join the film covering the nuclear membrane, granules are seen similar to 
those in the rest of the cytoplasm. The drawing — an ink copy of the original 
pencil drawing — is inaccurate, for these granules upon the nuclear contour should 
be shown as lying wholly outside (though abutting upon) the membrane. > 9YO 
diameters. 
Fig. 206. A danghter cell from the division of a zygote similar to that 
shown in Fig. 204; from a tadpole of Bombinator pachypus, infected 7 days. 
Acetic acid. >< 673 diameters. 
Fig. 207. An unclear acetic-carmine preparation from a tadpole of Bom- 
binator pachypus, infected 91 hours. >< 673 diameters. 
Fig. 208. An acetic-acid preparation from a tadpole of Bombinator pachypus, 
infected 7 days. A spindle-shaped microgamete nucleus lay near what seemed to 
be four daughter nuclei. > 673 diameters. 
