KLEDONE. DDD 
olfactory in function. More probably it is some kind of 
taste organ. Its function may be the testing of the water 
which enters the branchial cavity. 
THe AUDITORY ORGAN. 
Kledone has one pair of statocysts, embedded in the 
ventral wall of the cranial cartilage, and therefore just 
below the sub-oesophageal nervous mass, between the 
pedal and visceral gangha. ‘The membranous statocyst is 
spherical, with a diameter of 6 mm., and lies in a 
spherical cavity of somewhat larger dimensions. ‘The 
organ is attached to its cartilaginous capsule by a network 
of fine arterial vessels, running to the wall of the vesicle 
(PI. VIII, fiz. 68, Aud.caps., Aud. ves.). The venous 
blood collects in the cavity of the capsule, and thence 
passes out to the anterior vena cava, along with the blood 
from the eye. Dorsally the smooth cartilaginous wall is 
pierced by the auditory nerve and artery. Internally a 
thin wall separates the two capsular cavities. 
The Statocyst itself is a spherical transparent 
structure, lined with a flattened epithelium. Its antero- 
dorsal wall is thickened into an oval pad, whose internal 
wall is covered with columnar cells, bearing numerous 
short cilia (fig. 67, s.d.). Besides this sensory pad, there 
is also a sensory ridge, which runs from the former round 
the dorsal wall of the vesicle, then over the ventral, and 
finally ends on the dorsal surface (fig. 67, s.r.). Between 
these two sensory regions is a low conical ridge which 
projects inwards from the wall of the vesicle (fig. 67, wr.). 
The auditory nerve originates in the cerebral 
ganglion, runs downwards, and leaving the pedal enters 
the statocyst dorsally, and bifurcates. One branch ends in 
the pad, whereas the other supplies the ridge, which is 
