PLATE LXXII. 



Zone of Amaltheus margaritatus. 



Fig. 1. Lytoceras fimbrtatum, Sowerby. Lateral view, natural size, showing radii and 



fimbriae. My collection. 



2. Front view showing aperture. 



3. — — Abdominal view, siphonal area, radii and 



fimbriae natural size. 



4. — — — Accurate delineation of the complicated 



suture line, magnified. 



