Category:Helcionelloida
Appearance
Articles relating to the Helcionelloida, an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell.
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
Wikimedia Commons has media related to Helcionelloida.
Subcategories
This category has the following 4 subcategories, out of 4 total.
Pages in category "Helcionelloida"
The following 14 pages are in this category, out of 14 total. This list may not reflect recent changes.