PLATE LXVI. 



Zone of Lytoceras Jurense. 



Fig. 1. Harpoceras insigne, Schubler. Side view, reduced half natural size. 



2. — — Front view of this variety, do. 



3. — — — Back view, do. do. 



This shell is contained in the Geneva Museum, and was collected in the Terrain 

 Toarcien of Thouars, Deux-Sevres, France. 



