CONCHOLOGIA CESTRICA. Ly, 
The Eye, is very small, and placed on, or near, the base 
of the tentacles, and consists of the usual coats pertaining 
to that organ, together with a lens. 
The Organ of Hearing, is composed of two auditive 
capsules, placed on the posterior surface of the large 
cesophageal ganglion (the brain). These capsules con- 
tain several otolites, or small spherical bodies, composed 
of carbonate of lime, immersed in a fluid, and possessing 
a rotary or vibratory motion, derived from the vibratile 
cilia within the capsules. 
The situation of the Olfactory Organ, has not been 
satisfactorily ascertained. In the terrestrial species, it 
is supposed to reside in a cal de sac, between the lower 
lip and the front of the foot. 
The Organ of Taste, is alike unknown; but that 
needful sense probably resides within the buccal cavity 
which contains the lingual ribbon. 
The Oral Organs, are highly complicated —the lip 
or palate is armed with a transverse arcuated maxillary 
plate or jaw, either entire, or consisting of several pieces; 
within this is an elongated strap of ligamentous or cor- 
neous matter, called the Tongue, or Lingual Ribbon; 
the surface of which is thickly set with Sharp Siliceous © 
Teeth, beautifully arranged in rows, both transverse 
and longitudinal, with the points turned inward. The 
number of denticles varies from a few hundreds, to 
many thousands. The tongue is very retractile, by its 
own proper muscles; and is an ingestive, as well as a 
manducatory organ. When in use, it is quickly pro- 
jected from the mouth in the form of a loop, and as 
rapidly withdrawn. 
The Alimentary Canal, is long, and convoluted, and 
some species are provided with Salivary Glands. 
The Kidneys, are sometimes present. 
The Liver, always. 
2x B 
