water, so that the posterior aperture of the mantle cavity is both inhalant and exhalant.
Inhalant forms of antiasthmatic drugs may cause dryness or irritation in the throat, dry mouth, or an unpleasant taste in the mouth.
When the edges of the mantle ventral to the inhalant orifice are united, an anterior aperture is left for the protrusion of the foot, and thus there are three pallial apertures altogether, and species in this condition are called " Tripora."
However, these problems are much less likely with the inhalant forms than with the oral and injected forms.
While the oral and injected forms generally should be used only for one to two weeks, the inhalant forms may be used for long periods.