Compare the external structure of gastropods and cephalopods and name the differences.

The main differences in the external structure of cephalopods and gastropods are determined by the differentiation in the development of body parts characteristic of all mollusks, such as the shell and the leg.
The shell in cephalopods is mostly rudimentary, and in the higher representatives of this class it is internal, often more or less simplified or completely disappears. In gastropods, the shell is external, in most cases spirally twisted. Hence another characteristic feature of all gastropods – the asymmetry of the structure. In contrast to them, the body of the cephalopods is symmetrical, with a sharp division into the head and trunk.
The leg in gastropods is well developed and presents a muscular abdominal outgrowth for crawling. In cephalopods, the front part of the leg during embryonic development turns into several grasping tentacles or arms around the mouth, and the back part forms a muscular funnel.