Step 1: Understanding the Concept:
Gastropods (snails) possess shell structures that grow as a coiled tube around a central axis.
Understanding gastropod shell terminology is essential for taxonomic identification.
Step 2: Detailed Explanation:
A typical gastropod shell consists of multiple coils called whorls:
- Body whorl: The last, largest whorl where the snail's body resides.
- Spire: The rest of the shell located above the body whorl, consisting of all the smaller, successive whorls coiled together.
- Apex: The very tip or oldest point of the shell.
- Umbilicus: A hollow cavity on the under-surface of some shells.
Step 3: Final Answer:
The series of whorls excluding the body whorl is the spire, which corresponds to option (C).