Esteruy. — Eucalanus. 
Fia. 
Fig. 
Fig. 
Fia. 
Fig. 
Fig. 
Fic. 
Fig. 
25. 
26. 
27. 
28. 
29. 
30. 
ol. 
32. 
PLATE 3. 
Dorsal aspect of part of a frontal section of the brain. Vom Rath’s 
fluid 18 hours, decolorized in hydrogen peroxide. It shows one 
cell of the right organ of Claus and its nerve in relation to the 
neuropil mass of the brain. The section is the most ventral of 
three which show the organ of Claus. The basal plate was re- 
moved with the two more dorsal sections, so it is evident that 
the nerve leaves the cell on the side opposite to that of the basal 
plate. x 405. 
The cell of the organ of Claus shown in Figure 25, enlarged to 665 
diameters, showing the course of the fibrillae and the arrangement 
of phaosomes. 
Anterior part of brain, organs of Claus and parts of optic nerve, 
frontal nerves, and antennal nerves. Entire preparation seen 
from dorsal side. Vom Rath’s fluid 18 hours, pyroligneous acid 
44 hours; decolorized. X 305. 
Right face of a sagittal section of an organ of Claus. Vom Rath’s. 
fluid 18 hours; decolorized. The general form of the two basal 
plates as seen in this section is the same as in cross sections 
(Plate 2, Fig. 18) or in frontal sections (Plate 2, Fig. 11). The 
interior bodies are rod-like and lie around the periphery of the 
cell. XX 665. 
The most dorsal of the frontal sections of the organ of Claus in the 
series of which Figure 26 is the most ventral. The intermediate 
bodies, part of the basal plate, and nerve are shown. ‘The nerve 
leaves the cell at a point opposite the basal plate. X 665. 
The middle section in the series shown in Figures 29, 30 and 26. 
The interior bodies are few compared with those found in the other: 
two sections, and the extent of the basal plates is greater. X 665. 
Ventral view of entire organ of Claus. Vom Rath’s fluid 18 hours,. 
pyroligneous acid 44 hours, decolorized. The deep (dorsal) 
cell has been drawn in detail (outline pale); the ventral cell is 
drawn with a sharp outline, but besides the outline only the nu- 
cleus and some phaosomes are reproduced. The basal plates 
are not shown in either cell. X 665. 
Anterior face of a cross-section of a part of the brain, the right organ 
of Claus and right antennal nerve. The organ of Claus, it will be 
observed, is on the opposite side of the brain from that shown in 
Plate 2, Figure 18. The difference between the two cases in the 
position of the line of contact of the two cells should be noted. 
xX 665. 
