THE EVIDENCE OF THE AUDITORY APPARATUS 363 
time, my preparations are not sufficiently clear to enable me to 
trace out the connections of these cells, especially their connections 
with the special sense- 
organs. 
In Fig. 148 I give a 
magnified representation 
of a section through three 
of these flabellar sense- 
organs. As is seen, the 
section divides itself into 
four zones: (1) the chi- 
tinous layer (ch.); (2) 
the layer of pigment (p.) 
and hypodermal cells; 
(3) the layer of ganglion- 
cells (gl.); and (4) the 
layer of nerve-fibres (7.) 
and blood-spaces (Ol.). 
The chitinous layer is 
composed of the usual 
three zones of the Li- 
iwulus surface — exter- 
nally (Fig. 148), a thin 
homogeneous layer, fol- 
lowed by a thick layer 
of chitin (3), in which 
the fine vertical tubules 
or canaliculi are well 
marked; the external 
portion (2) of this layer 
is differentiated from the 
rest by the presence of 
well-marked horizontal 
layers in addition to the 
canaliculi. 
In this chitinous layer 
the special sense-organs 
Fig. 148.— SECTION THROUGH THREE SENSE- 
ORGANS OF FLABELLUM. 
bl., blood-spaces; 7., nerve; gl., layer of ganglion- 
cells; p., pigment layer; ch., 1, 2, 3, the three 
layers of chitin; ch.t., chitinous tubule in large 
tube of sense-organ ; cap., capitellum or swollen 
extremity of large tube; can., very fine porous 
canals or canaliculi of chitin, 
are found. They consist of a large tube which passes through all the 
layers of the chitin except the thin homogeneous most external layer. 
