10 MOLLUSCA. 
liantly-painted shells, which throng the damp 
woods in tropical countries, likewise belong to this 
group, and furnish the most highly prized treasures 
of our conchological cabinets. In these the air is 
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9 
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on eo 
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PEROPHORA. 
inhaled into an ample chamber, the interior of 
which is lined with cilia. After parting with its 
oxygen, it is again expelled; the common orifice 
for both processes being situated on the side of the 
