GASTROPODA, the second of the five classes of animals constituting the phylum Mollusca.
The Phylum Vertebrata in the above scheme branches into the sub-phyla Hemichorda, Urochorda, Cephalochorda and Craniata.
This revolution may be accomplished by adding the term " mutation ascending " or " mutation descending " for the minute steps of transformation, and the term phylum, as employed in Germany, for the minor and major branches of genetic series.
Ope yxta, gills), the fourth of the five classes of animals constituting the phylum Mollusca.
CHITON, the name 1 given to fairly common littoral animals of rather small size which belong to the phylum Mollusca, and, in the possession of a radula in the buccal cavity, resemble more especially the Gastropoda.