Cypraea (Zoila) mariellae?

Please could someone help me with this?.

There is very little information about this shell available online.  
I was given it by a friend he worked on a trawler, around 5 years ago, 
he has passed away a year ago.

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Bonjour

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Can someone pretty please explain how identification works with shells?
And being from South Australia selling this particular one?
I don't plan on keeping this one, id like to move it along if possible

Bonjour
Il ne s'agit pas d'une mariellae. 
J'y vois une thersites contraria sub-adulte.