Light (A-C) and scanning electron (D-I) micrographs of Longinebela ampulla. (A-E) Broad lateral views to illustrate characteristic form of the ampoule. (F) Narrow lateral view showing absence of lateral compression, lateral margins and pores. (G) Broad lateral view of the apertural region to show distinct short neck and shell strucrure. (H) Apertural view showing aperture outline and thin apertural collar. (I) Detail of shell surface showing shell plates and abundant organic cement.