PLATE LXXII. 



Zone of Avmlthem marfjaritatus. 



Fig. 1. Lytoceras FiMBRiATUM, -iSo?^er<^^. 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 dehneation of the complicated 



suture line, magnified. 



