PULMONATE

(subclass Pulmonata), any of various land and freshwater (a few marine) snails, class Gastropoda, that breathe by means of a lunga saclike modification of the mantle cavity. The slugs lack an external shell, but most pulmonates have a spiral shell that may be attenuated or flattened. They are anatomically more advanced than other snails: all are detorted (bilaterally symmetrical, with an unlooped nerve cord) as adults, and the auricle of the heart is anterior to the ventricle. All are hermaphroditici.e., with both male and female reproductive organs in one animal.