1. Elephant tusk shell as a general description:
This could refer to any shell that resembles an elephant tusk in shape. Many marine snails and bivalves have elongated, curved shells that could be described as "elephant tusk-like".
2. A specific species:
If you heard this term used in a specific context, it's possible it referred to a particular species of marine mollusk. To identify the specific species, you would need more information about where you heard it, what the context was, or even a picture of the shell.
3. A misnomer:
It's possible that "elephant tusk shell" is simply a misnomer. It could be a nickname or a colloquial term that is not widely recognized.
To get a more accurate answer, please provide more information:
* Where did you hear the term "elephant tusk shell"?
* What was the context?
* Do you have a picture of the shell?
With more information, I can help you identify the specific species or understand the term better.