7. Genus Pyrula. Pl. [XI].

Animal. Unknown.

Shell. Pyriform on account of the depression of the spire, which distinguishes it from the Fusus; the canal conical, very long or middling, sometimes a little sloped; aperture oval, rather large; the columella edge somewhat excavated, entire and trenchant; an operculum. Found in the Northern and American seas. Twenty-nine living species. Six fossil.

8. Genus Struthiolaria. Pl. [XI].

Animal. See Triton, hereafter.

Shell. Ovate; spire prolonged; aperture sinuous, terminated at the base by a very short, straight canal: columellar edge callous; right edge having a thickened varix. Inhabits the Mediterranean and Northern Seas. Two species.

9. Genus Ranella. Pl. [XI].