This trilobite fossil is a
Flexicalymene senaria Conrad.
The fossil was found in Indiana USA. This creature existed in the oceans of the Ordovician Period.
It was displayed at Muséum National D'Historie Naturelle Jardin Des
Plantes Paléontologie et Anatomie Comparée as of August 2016.
Image below was taken August 2009 on a visit to the same museum.