362 M. M. Mercarr 
shown. The achromatic structures (except the nucleolus), the finerthreads of the 
chromatin net, and the details of form of the chromosomes are omitted from the 
figure. Coros. subl.-acetic acid, Denarrep’s haematoxylin. > 1600 diameters. 
Fig. 76. An individual with its nuclei in what may perhaps be called the 
resting condition. Only the chromatin masses and the larger vacuoles of the 
achromatic foam are shown. Coros. subl.-acetic acid, Detarrerp’s haematoxylin. 
< 808 diameters. 
Fig. 77. The posterior nucleus shown in Fig. 76. Only the achromatic foam 
and the chromatin masses are shown, the nucleolus and the chromatin net being 
omitted. > 1600 diameters. 
Fig. 78. An anterior nucleus drawn to show a weakly stained chromatin 
spherule in a tubular process from the anterior end of the nucleus. The chromatin 
masses also are drawn. Coros. subl.-acetic acid, DeLarreLp’s haematoxylin. > 1600 
diameters. 
Fig. 79. A nucleus similar to that drawn in Fig. 78, showing several par- 
tially dissolved (weakly stained) chromatin spherules, one of which lies in a pro- 
jection from the anterior end of the nucleus. All achromatic structures and the 
chromatin net are omitted from the drawing. Coros. subl.-acetic acid, DELAFIELD’s 
haematoxylin. >< 1600 diameters. 
Fig. 80. A dumbbell-shaped nucleus of a daughter cell. A few partially 
dissolved chromatin spherules are seen in each end of the nucleus. The chromatin 
net, the nucleolus, and all the other achromatic structures except a few granules 
are omitted from the drawing. Coros. subl.-acetic acid, Deiarrep’s haematoxylin. 
< 1600 diameters. 
Figs. 81—92. Opalina caudata. 
Fig. 81. An individual with each of its nuclei in a late anaphase of mitosis. 
Six chromosomes are seen in each end of each nucleus. The spherical bodies at 
the centers of the nuclei are the nucleoli. The achromatic foam and the finer 
fibres of the chromatin net are omitted from the figure. Coros. subl.-acetic acid, 
borax carmine. >< 246 diameters. 
Fig. 82. A daughter cell showing the nucleolus in the anterior daughter 
nucleus, and six chromosomes in each nucleus; some of these are already united 
preparatory to forming the chromatin ribbon. Coros. subl.-acetic acid, borax car- 
mine. X< 262 diameters. 
Fig. 83. A section of a nucleus showing granular chromatin masses, some 
fibres of the chromatin network with darkly stained nodal thickenings, and some 
films and granules (lightly stained) of the achromatic foam. Observe that the 
granules in the chromatin masses are of various sizes and shapes. Coros. subl.- 
acetic acid, iron haematoxylin. > 1188 diameters. 
Fig. 84. Part of a section of a nucleus, showing one granular chromatin 
mass, and a few other granules probably achromatic. Near the nucleus is shown 
a single granular endosare spherule. Coros. subl.-acetic acid, iron haematoxylin. 
x 1188 diameters. 
Fig. 85. Part of a longitudinal section, showing one nucleus and a little of 
the adjacent cytoplasm. This nucleus was in an anaphase of mitosis. In order 
to show more clearly the chromatin granules upon the chromatin net these are 
drawn much darker than the chromosomes and the fibres of the chromatin net. 
