FIG. 11. Brachial valve nearly ground away, to show spire. The sickle-shaped structure is probably the base of the opposite spire. Beede’s collection. FIG. 12. Specimen with brachial valve largely broken away. All specimens but No. 11 in collection of University of Kansas. [Illustration: PLATE VI.] ------------------------------------------------------------------------ TRANSCRIBER’S NOTES 1. Silently corrected obvious typographical errors and variations in spelling. 2. Retained archaic, non-standard, and uncertain spellings as printed. 3. Enclosed italics font in _underscores_. 4. Enclosed bold font in =equals=.