Opalina. 367 
Fig. 151. An optical section of a macrogamete from a tadpole of Bombinator 
pachypus, infected 6 days. Acetic-carmine. > 673 diameters. 
Fig. 152. A section (4 «) of a macrogamete or macrogamete parent-cell in 
the rectum of a tadpole of Bombinator pachypus, infected 24 hours. Coros. subl.- 
acetic acid, Drnarietp’s haematoxylin. X 1334 diameters. 
Fig 153. <A living dividing gamete parent-cell from a tadpole of Bufo 
vulgaris, infected 42 hours. Extruded excretory granules are seen at the posterior 
end of the body. The long and sparce cilia make it probable that (after not less 
than two divisions) this cell will give rise to microgametes. >< 673 diameters. 
Plate XXIII. 
Opalina intestinalis. 
All figures are reduced one-third, to the magnification indicated. 
Fig. 154. A microgamete parent-cell from a tadpole of Bombinator pachypus, 
infected 70 hours. The cilia are taken from a sketch of the living animal; the 
body fourm and nucleus were drawn after treatment with acetic-carmine. > 673 
diameters. 
Figs. 155 158. Microgamete parent-cells from a tadpole of Bombinator 
pachypus, infected 70 hours. In Fig. 155 parts of the excretory organ are seen. 
Acetic-carmine. > 673 diameters. 
Fig 159. A living microgamete parent-cell in division, from a tadpole of 
Bombinator pachypus, infected 70 hours. The cilia are too short. >< 1010 diameters. 
Fig. 160. A living cell ready to metamorphose into a microgamete, from a 
tadpole of Bombinator pachypus, infected 42 hours. I suspect that the posterior 
two or three cilia were attached further forward than is shown, since the naked 
end of the tail is longer in the fully formed microgamete than in this animal as 
here drawn. XX 673 diameters. 
Figs. 161 and 162. Microgametes (the first mature, the second probably 
not so) whose tails are contracted by acetic-carmine; from tadpoles of Bombinator 
pachypus, infected 91 hours (Fig. 161) and 70 hours (Fig. 162). In Fig. 161 the 
endosare spherules are drawn. X< 675 diameters. 
Fig. 163. A living microgamete from a tadpole of Bufo vulgaris, infected 
42 hours. Accurately drawn, except that the nuclear structure, which was not 
clear, is omitted. The endosare spherules are shown. XX 673 diameters. 
Fig. 164. An early stage of copulation. From life. The animals were too 
active for drawing with the camera. The record of the infection from which these 
animals were obtained is lost. Some cilia have been added to the microgamete 
in the original sketch, which represented rather too thin an optical section. 
(Cf. Mercanr 1907a, Fig 3.) : 
Figs. 165—167 Later stages of copulation in different individuals from a 
tadpole of Bombinutor pachypus, infected 88 hours. Free hand drawings from life. 
Fig. 168. A copulating pair from a tadpole of Bombinator pachypus infected 
88 hours. The nucleus of the male seemed to contain two chromatin masses of 
unequal size, but the staining was not sufficiently clear to determine accurately 
the structure. Probably the larger mass was composed of three chromosomes 
lying close together. Acetic-carmine. X< 673 diameters. 
Fig. 169. An early stage of copulation, from a tadpole of Bombinator pachypus, 
infected 70 hours. Acetic-carmine. X 693 diameters. 
