The peculiarities of the Gastropoda are all due to the torsion of the shell and body.
In the majority of Gastropoda one gill and one auricle are lost.
In the larvae of several Gastropoda and Lamellibranchia occur excretory organs which have the characters of true nephridia.
GASTROPODA, the second of the five classes of animals constituting the phylum Mollusca.
For a discussion of the relationship of the Gastropoda to the remaining classes of the phylum, see MoLLUSCA.