Perisphinctid fossil ammonites from the late Jurassic formations near Tulear, Madagascar for sale.
Sold to us as examples of Perisphinctes, these are in reality members of genus Aulacosphinctoides.

The specimens we currently have for sale are all genus Aulacosphinctoides  of various species. 

Ref. Collignon, M.; ATLAS DES FOSSILES CARACTERISTIQUES DE MADAGASCAR, Fascicule VI, (TITHONIQUE) Service Geologique, Tananarive 1960.