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Explanation of Plates. 
All figures are camera drawings unless otherwise indicated. The degree of 
accuracy of all figures is told. When nothing is said as to accuracy, everything 
shown is carefully drawn with the camera; omissions are not always noted. Draw- 
ings from acetic-carmine preparations cannot show fine details for the stain does 
not bring out the finer structure. 
Plate XIV. 
Fig. 1. A schematic drawing of an optical longitudinal section of O. intestinalis, 
showing cilia, basal granules of cilia, ectosare with ectosarc spherules (gray), endo- 
sare with endosare spherules (black), axial excretory organ, two nuclei (connected 
by a thread) each containing eight chromosomes. In the posterior nucleus is seen 
the vacuolated nucleolus. 
Fig. 2. Part of a tangential section (superficial) of O. ranarum. Two rows 
of basal granules of the cilia are shown. Above each of these rows is a fibril 
which probably connects the outer ends of the basal granules. Transverse fibrils, 
at a little lower level than the last, run between the basal granules. The two 
longitudinal striae between the rows of basal granules are probably ridges in the 
pellicula. Where they cross over the transverse fibrils one sees a misleading 
hazy appearance of granules which do not exist. Coros. subl.-acetic acid, iron 
haematoxylin. >< 4100 diameters. 
Fig. 3. Part of an oblique section of O. intestinalis, showing cilia (diagram- 
matically drawn), pellicula, basal granules of cilia, five alveoles of the ectosarc, 
two ectosarc spherules with contained granules, and two endosare spherules with 
contained granules. Coros. subl.-acetic acid, iron haematoxylin. > 2000 diameters. 
Fig. 4. A cross section of O. intestinalis, showing the endosarc spherules 
(black) and the ectosare spherules (gray). No attempt to indicate protoplasmic 
structure is made, merely the large alveoles of the ectosare being drawn. Coros. 
subl.-acetic acid, iron haematoxylin (but little extracted). >< 145 diameters. 
Fig. 5. Part of a longitudinal section of O. intestinalis, showing cilia 
(slightly diagrammatic), basal granules of cilia, granular spherules in ectosare 
and endosare, cytoplasmic granules, nucleus with three large granular masses of 
chromatin and granular achromatic foam, also three chromatin spherules seeming 
about to be extruded from the nucleus. The small faintly stained spherical body 
in the nucleus is probably a partly dissolved chromatin spherule. The arrows in- 
