THE LEECHES OF JAPAN. 399 
large rounded cells (g.) which appear to be ganglionic in 
nature. The peripheral cells of the bulb are densely packed, 
thread-like cells, with pyriform inner (nucleated) ends. The 
terminal portions of these cells present a rod-like appearance in 
the apical region of the bulb, and are here more highly refrac- 
tive than elsewhere. The cuticle extends over the whole 
external surface of the bulb, but becomes very thin over the 
circular apical area which is marked by the refractive rod-like 
ends of the sensory cells. So far as I have been able to learn, 
these elongated peripheral cells of the bulb are never prolonged 
beyond the cuticle. The same rod-shaped, refractive end por- 
“tions are seen in the goblet-shaped sense-organs of the lip and 
in the eyes. 
In Hirudo and Heemadipsa these organs have the form seen 
in Fig. 4. The same elements enter into the composition of the 
organ. The sense-cells are more elongated, and often collected 
in small groups, to each of which runs a distinct branch of 
the nerve. 
Fig. 4.—Section of one of the inner lateral sense-organs of Macrobdella in a 
state of retraction. c. Cuticle. ep. Hpidermic cells. yg. Ganglion cells. 
p. Large clear cells, x. Nerve-fibres. 
